FORM 2
THE PATENTS ACT, 1970 (39 of& 1970) THE PATENTS RULES, 2003 COMPLETE SPECIFICATION
[See section 10, Rule 13]
AIR CONDITIONER;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED
AND EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
Field
[0001] The present invention relates to an air
conditioner that executes temperature protection 5 control of
a motor.
Background
[0002] In conventional temperature protection control of
10 a DC (Direct Current) motor, a temperature protector is
attached to the DC motor, and power supply of a motor
driving element is shut down when the temperature of a
winding of the DC motor reaches a predetermined temperature
or higher. Due to this operation, the motor driving
15 element is forcibly stopped to stop the operation of the DC
motor, thereby protecting the DC motor (see, for example,
Patent Literature 1).
Citation List
20 Patent Literature
[0003] Patent Literature 1: Japanese Patent Application
Laid-open No. 2012-228009
Summary
25 Technical Problem
[0004] In the technique described in Patent Literature 1
described above, when a temperature abnormality caused by
abnormal heat generation in a winding of a DC motor occurs,
the power supply of a motor driving element is shut down,
30 to forcibly stop the motor driving element and stop the
operation of the DC motor. In such stoppage operation,
however, functions other than the motor driving element are
still in an operable state. Usually, while the power
3
supply of the motor driving element is shut down, the motor
driving element is opened, and therefore a path of an
electric current to the DC motor is not formed and so any
current does not flow to the DC motor. However, even while
the power supply of the motor driving element 5 is shut down,
in a case where the motor driving element is shortcircuited
and a path of an electric current to the DC motor
is formed, a current can flow to the DC motor if a powersupply
voltage that is a source of a driving voltage for
10 the DC motor is applied to the motor driving element. This
situation has been problematic.
[0005] The present invention has been achieved in view
of the above circumstances, and an object of the present
invention is to provide an air conditioner that is capable
15 of, in a case where a temperature abnormality due to
abnormal heat generation in a motor is caused, preventing a
current from flowing to the motor even if a motor driving
element is short-circuited.
20 Solution to Problem
[0006] In order to solve the above-mentioned problems
and achieve the object, the present invention provides an
air conditioner comprising an indoor unit and an outdoor
unit, wherein the outdoor unit includes: a motor; a first
25 relay including a first coil part and a first contact part
provided on a supply line of an alternating current power
supply that is a power supply of the outdoor unit, in which
the first contact part is placed in an electricallydisconnected
state when any current does not flow through
30 the first coil part and the first contact part is placed in
an electrically-connected state when a current flows
through the first coil part; a PTC (Positive Temperature
Coefficient) connected in parallel to the first contact
4
part; and a temperature protector provided on a supply line
of a relay-driving power supply that is a power supply of
the first relay and provided to the motor, which is in an
electrically-connected state when a temperature of the
motor is lower than a predetermined temperature, 5 and is
placed in an electrically-disconnected state when the
temperature of the motor reaches a predetermined
temperature or higher.
10 Advantageous Effects of Invention
[0007] The air conditioner according to the present
invention has an advantageous effect that, in a case where
a temperature abnormality is caused by abnormal heat
generation in a motor, it is possible to prevent a current
15 from flowing to the motor even if a motor driving element
is short-circuited.
Brief Description of Drawings
[0008]
20 FIG. 1 is a schematic configuration diagram
illustrating an example of an air conditioner according to
a first embodiment of the present invention.
FIG. 2 is a flowchart of a process of detecting a
temperature abnormality of a winding of a DC motor to stop
25 the DC motor, which is performed by an outdoor unit
illustrated in FIG. 1.
FIG. 3 is a schematic configuration diagram
illustrating an example of an air conditioner according to
a second embodiment of the present invention.
30 FIG. 4 is a schematic configuration diagram
illustrating an example of an air conditioner according to
a third embodiment of the present invention.
FIG. 5 is a flowchart of a process of detecting a
5
temperature abnormality of a winding of a DC motor to stop
the DC motor, which is performed by the air conditioner
illustrated in FIG. 4.
Description 5 of Embodiments
[0009] An air conditioner according to embodiments of
the present invention will be described in detail below
with reference to the drawings. The present invention is
not necessarily limited by these embodiments.
10 [0010] First embodiment.
First of all, an air conditioner according to a first
embodiment of the present invention is described. FIG. 1
is a schematic configuration diagram illustrating an
example of the air conditioner according to the first
15 embodiment of the present invention.
[0011] An air conditioner 100 illustrated in FIG. 1
includes an outdoor unit 1 and an indoor unit 2. The
outdoor unit 1 includes a DC motor 3 such as a compressor
motor or a fan motor, an outdoor control board 4 configured
20 to control the DC motor 3, and a temperature protector 5
configured to protect the DC motor 3 against a temperature
abnormality. The outdoor unit 1 may include an AC
(Alternating Current) motor, for example, in place of the
DC motor 3.
25 [0012] The outdoor control board 4 includes an inrushcurrent
prevention circuit 6 configured to protect the
outdoor control board 4 against an inrush current, a diode
bridge 8 configured to rectify an AC current supplied from
an AC power supply 7, an electrolytic capacitor 9 that
30 accumulates electric charges therein, and a DC/DC converter
10. The DC/DC converter 10 converts an applied DC voltage
into a low DC voltage for causing each part on the outdoor
control board 4 to operate, and converts the applied DC
6
voltage into a DC voltage that is used as a source to be
converted to a driving voltage by a motor driving element
11. The DC voltage having a low voltage value, which has
been generated by the DC/DC converter 10 is applied to each
part on the outdoor control board 4 5 through a path not
illustrated in FIG. 1. The outdoor control board 4
includes the motor driving element 11 configured to drive
the DC motor 3, an outdoor microcomputer 12 configured to
transmit a driving instruction signal for the DC motor 3 to
10 the motor driving element 11 and control the inrush-current
prevention circuit 6, and an outdoor communication circuit
14 configured to transmit information to and receive
information from an indoor control board 13 described later.
[0013] The indoor unit 2 includes the indoor control
15 board 13. The indoor control board 13 includes an indoor
power-supply circuit 15 configured to convert the AC power
supply 7 into a power supply for causing each part on the
indoor control board 13 to operate, an indoor microcomputer
16 configured to control functions of the indoor unit 2,
20 and an indoor communication circuit 17 configured to
transmit information to and receive information from the
outdoor control board 4. The outdoor unit 1 and the indoor
unit 2 are connected to each other through the outdoor
communication circuit 14, an indoor-outdoor communication
25 line 26, and the indoor communication circuit 17.
[0014] The inrush-current prevention circuit 6 includes
an inrush-current prevention relay 18 and a PTC (Positive
Temperature Coefficient) 19 connected in parallel to a
contact part 20b of the inrush-current prevention relay 18.
30 The PTC 19 is a PTC thermistor, for example. The inrushcurrent
prevention relay 18 has a configuration in which a
relay-driving power supply 21 is connected to one end of a
coil part 20a through the temperature protector 5, the
7
outdoor microcomputer 12 is connected to the other end of
the coil part 20a, and the contact part 20b is brought into
an electrically-connected state when an electric current is
caused to flow through the coil part 20a by control of the
outdoor microcomputer 12, and 5 is brought into an
electrically-disconnected state when an electric current is
not caused to flow through the coil part 20a. The contact
part 20b is provided on a supply line A of the AC power
supply 7 on the outdoor control board 4. The inrush10
current prevention relay 18 corresponds to a first relay.
The coil part 20a corresponds to a first coil part. The
contact part 20b corresponds to a first contact part.
[0015] The temperature protector 5 is in a state where
both ends of the protector are electrically connected to
15 each other when the temperature of an object is lower than
a predetermined temperature, but cuts off the electrical
connection between the both ends to enter into the
electrically-disconnected state when the temperature of the
object reaches a predetermined temperature or higher. The
20 temperature protector 5 is attached to an outer wall, a
winding, or the like of the DC motor 3 as the object to be
protected. The temperature protector 5 has one end
connected to the coil part 20a and the other end connected
to the relay-driving power supply 21. The temperature
25 protector 5 is provided on a supply line B of the relaydriving
power supply 21. The temperature protector 5 may
be connected to the coil part 20a at one end thereof and to
the outdoor microcomputer 12 at the other end thereof. The
temperature protector 5 is, for example, a thermostat. The
30 temperature protector 5 is not limited to a type of a
switch, and may be a type in which the electrical
connection between both terminals thereof is cut off
depending on the temperature such as a thermal fuse.
8
[0016] FIG. 2 is a flowchart of a process of detecting a
temperature abnormality of a winding of a DC motor to stop
the DC motor, which is performed by an outdoor unit
illustrated in FIG. 1.
[0017] In the outdoor unit 1, when 5 an AC current is
supplied from the AC power supply 7 to the outdoor control
board 4, the supplied AC current passes through the PTC 19
of the inrush-current prevention circuit 6 and is then
rectified by the diode bridge 8, and electric charges are
10 accumulated in the electrolytic capacitor 9. In this
situation, an AC voltage applied from the AC power supply 7
to the outdoor control board 4 is converted into a DC
voltage.
[0018] The DC voltage obtained by the conversion is
15 converted by the DC/DC converter 10 into a DC voltage
having a low voltage value, required for operations of
elements such as the outdoor microcomputer 12, the motor
driving element 11, and the outdoor communication circuit
14, and is applied to parts constituting elements such as
20 the outdoor microcomputer 12, the motor driving element 11,
and the outdoor communication circuit 14. The power-supply
voltage of the relay-driving power supply 21 is also a DC
voltage having a low voltage value and is generated by the
DC/DC converter 10.
25 [0019] When the generated low DC voltage is applied to
the outdoor microcomputer 12, the outdoor microcomputer 12
is activated. The outdoor microcomputer 12 executes
control in such a manner that the power-supply voltage of
the relay-driving power supply 21 is applied to the coil
30 part 20a and an electric current flows through the coil
part 20a. Accordingly, the contact part 20b forms
connection, so that the AC current that has been supplied
to the diode bridge 8 through the PTC 19 starts to be
9
supplied to the diode bridge 8 through the contact part 20b,
and then the path of the AC current is switched.
[0020] Usually, a time to switch over the path of the AC
current requires only about one to two seconds. Therefore,
the amount of heat generation of the PTC 19 5 is not so large,
and the resistance value of the PTC 19 does not reach a
level at which supply of the AC current to the inrushcurrent
prevention circuit 6 and its subsequent units is
shut down.
10 [0021] After the path of the AC current is switched over,
a DC motor driving signal is transmitted from the outdoor
microcomputer 12 to the motor driving element 11, and a DC
voltage different from the low DC voltage described above,
which has been generated by the DC/DC converter 10, is
15 converted by the motor driving element 11 into a driving
voltage for causing the DC motor 3 to rotate. Application
of the driving voltage to the DC motor 3 causes the DC
motor 3 to rotate. The outdoor unit 1 performs a normal
operation in this manner (Step S101).
20 [0022] While a temperature abnormality caused by
abnormal heat generation in a winding of the DC motor 3
does not occur (NO at Step S102), the outdoor unit 1
performs a normal operation (Step S101).
[0023] When a temperature abnormality caused by the
25 abnormal heat generation in the winding of the DC motor 3
occurs (YES at Step S102), the temperature protector 5
operates (Step S103), so that the electrical connection
between both ends of the temperature protector 5 is cut off
and the power-supply voltage of the relay-driving power
30 supply 21 applied to the coil part 20a is cut off (Step
S104). Accordingly, the contact part 20b is opened (Step
S105).
[0024] Because the path of the AC current is switched
10
from a path passing through the contact part 20b to a path
passing through the PTC 19, the temperature and the
resistance value of the PTC 19 increase (Step S106) and a
voltage drop in the PTC 19 becomes larger. Accordingly,
the AC current is no longer supplied to 5 the inrush-current
prevention circuit 6 and its subsequent units, so that
electric charges cannot be accumulated in the electrolytic
capacitor 9 and a DC voltage applied to the DC/DC converter
10 decreases (Step S107).
10 [0025] When the DC voltage applied to the DC/DC
converter 10 decreases, the DC voltage applied to the motor
driving element 11 also decreases, and the motor driving
element 11 cannot generate a driving voltage (Step S108)
and so the DC motor 3 is stopped (Step S109). The DC/DC
15 converter 10 also becomes unable to generate the low DC
voltage required for the operations of the outdoor
microcomputer 12, the motor driving element 11, and the
outdoor communication circuit 14, and then the outdoor unit
1 is stopped.
20 [0026] When the power supply to the DC motor 3 is
stopped and any current does not flow through the winding
of the DC motor 3, the temperature of the winding of the DC
motor 3 decreases, and the temperature protector 5 is
returned to a state where both ends thereof are
25 electrically connected to each other. If the temperature
protector 5 is a thermal fuse, it is not returned to its
original state.
[0027] Even if the temperature of the PTC 19 decreases
and the resistance value of the PTC 19 is reduced to a
30 value at which a current flows therethrough, the powersupply
voltage of the relay-driving power supply 21 is not
generated by the DC/DC converter 10, and therefore the
contact part 20b remains opened even after the temperature
11
protector 5 is returned to the state where the both ends of
the protector are electrically connected to each other.
Therefore, even if accumulation of electric charges in the
electrolytic capacitor 9 starts again, an AC current flows
through the PTC 19, thereby causing the 5 temperature of the
PTC 19 to rise immediately and causing the resistance value
thereof to increase to a value at which a current flow is
stopped. As a result of this, accumulation of electric
charges into the electrolytic capacitor 9 is stopped.
10 Restart and stop of accumulation of electric charges in the
electrolytic capacitor 9 are repeated, and the DC voltage
applied to the DC/DC converter 10 does not increase to the
DC voltage required for voltage conversion of the DC/DC
converter 10. For this reason, the DC/DC converter 10
15 cannot generate the low DC voltage required for the
operations of the outdoor microcomputer 12 and so on, and
the DC voltage that is a source for conversion of the
driving voltage by the motor driving element 11. This
means that the outdoor unit 1 of the air conditioner 100
20 does not restart its operation unless the AC current
supplied to the outdoor control board 4 is cut off once by
using a breaker or the like and the temperature of the PTC
19 decreases to a temperature substantially equivalent to
the temperature at the operation start for a normal
25 operation.
[0028] According to the process illustrated in FIG. 2,
when a temperature abnormality caused by abnormal heat
generation in the winding of the DC motor 3 occurs, any AC
current is not supplied to the inrush-current prevention
30 circuit 6 and its subsequent units. Therefore, even if the
motor driving element 11 is short-circuited, any current
does not flow to the DC motor 3, and a current flowing
through the DC motor 3 can be cut off.
12
[0029] According to the present embodiment, the DC motor
3 is not stopped by control of the outdoor microcomputer 12.
Therefore, even if a function of protecting the DC motor 3
using a program in the outdoor microcomputer 12 does not
work for some reason such as a program 5 runaway in the
outdoor microcomputer 12, it is possible to stop the DC
motor 3.
[0030] According to the present embodiment, a voltage
applied across the temperature protector 5 is low, as
10 compared with that in a configuration in which a path of an
AC current supplied from the AC power supply 7 is
disconnected directly by a temperature protector. In
general, a component whose rated voltage is lower has a
smaller component size and it is therefore possible to
15 downsize the temperature protector 5.
[0031] Second embodiment.
Next, an air conditioner according to a second
embodiment of the present invention is described. FIG. 3
is a schematic configuration diagram illustrating an
20 example of the air conditioner according to the second
embodiment of the present invention. An air conditioner
100A according to the second embodiment of the present
invention is different from the first embodiment described
above mainly in that an AC current supplied from the AC
25 power supply 7 is not directly supplied to an outdoor unit
1A, but is supplied thereto through an indoor unit 2A.
Descriptions of configurations and effects overlapping with
those of the first embodiment are omitted, and
configurations and effects different from those of the
30 first embodiment are described below.
[0032] The air conditioner 100A illustrated in FIG. 3
includes the outdoor unit 1 and the indoor unit 2A. The
indoor unit 2A includes an indoor control board 13A. The
13
indoor control board 13A includes an indoor power-supply
circuit 15A configured to convert the AC power supply 7
into a power supply for causing each part on the indoor
control board 13A to operate, an indoor microcomputer 16A
configured to control functions of the indoor 5 unit 2A, and
an indoor communication circuit 17A configured to transmit
information to and receive information from the outdoor
control board 4. The outdoor unit 1A and the indoor unit
2A are connected to each other through the outdoor
10 communication circuit 14, the indoor-outdoor communication
line 26, and the indoor communication circuit 17A.
[0033] The indoor control board 13A includes an outdoor
power-supply relay 22. The outdoor power-supply relay 22
has a configuration in which a relay-driving power supply
15 24 is connected to one end of a coil part 23a and the
indoor microcomputer 16A is connected to the other end of
the coil part 23a, by which a contact part 23b is placed in
an electrically-connected state when an electric current is
caused to flow through the coil part 23a and the contact
20 part 23b is placed in an electrically-disconnected state
when an electric current is caused not to flow through the
coil part 23a under control of the indoor microcomputer 16A.
The contact part 23b is provided on a supply line C of the
AC power supply 7 on the indoor control board 13A. The
25 outdoor power-supply relay 22 corresponds to a second relay.
The coil part 23a corresponds to a second coil part. The
contact part 23b corresponds to a second contact part.
[0034] The present embodiment can obtain effects
identical to those in the first embodiment of the present
30 invention described above. Further, in the present
embodiment, the contact part 23b of the outdoor powersupply
relay 22 is provided on the supply line C of the AC
power supply 7 on the indoor control board 13A. By this
14
configuration, it is possible to cut off an AC current
supplied to the outdoor control board 4 even if cutting-off
of the AC current using a breaker or the like does not take
place.
[0035] 5 Third embodiment.
Next, an air conditioner according to a third
embodiment of the present invention is described. FIG. 4
is a schematic configuration diagram illustrating an
example of the air conditioner according to the third
10 embodiment of the present invention. An air conditioner
100B according to the third embodiment of the present
invention is different from the second embodiment described
above mainly in that the temperature protector 5 is not
provided between the relay-driving power supply 21 and the
15 inrush-current prevention relay 18, and instead a
temperature protector 5A is provided between a
communication-circuit power supply 25 and the outdoor
communication circuit 14. Descriptions of configurations
and effects overlapping with those of the second embodiment
20 are omitted and configurations and effects different from
those of the second embodiment are described below.
[0036] The air conditioner 100B illustrated in FIG. 4
includes an outdoor unit 1A and the indoor unit 2A. The
outdoor unit 1A includes the DC motor 3, an outdoor control
25 board 4A, and the temperature protector 5A. The
temperature protector 5A is attached to an outer wall, a
winding, or the like of the DC motor 3. The temperature
protector 5A is connected to the outdoor communication
circuit 14 at one end thereof and to the communication30
circuit power supply 25 at the other end thereof. The
temperature protector 5A is provided on a supply line D of
the communication-circuit power supply 25.
[0037] FIG. 5 is a flowchart of a process of detecting a
15
temperature abnormality of a winding of a DC motor to stop
the DC motor, which is performed by the air conditioner
illustrated in FIG. 4.
[0038] In the indoor unit 2A, an AC voltage applied to
the indoor power-supply circuit 15A 5 from the AC power
supply 7 is converted by the indoor power-supply circuit
15A into a low DC voltage required for operations of
elements such as the indoor microcomputer 16A and the
indoor communication circuit 17A, and the DC voltage is
10 applied to each part constituting elements such as the
indoor microcomputer 16A and the indoor communication
circuit 17A. The power-supply voltage of the relay-driving
power supply 24 is also a low DC voltage and is generated
by the indoor power-supply circuit 15A.
15 [0039] When the generated low DC voltage is applied to
the indoor microcomputer 16A, the indoor microcomputer 16A
is activated. The indoor microcomputer 16A executes
control in such a manner that the power-supply voltage of
the relay-driving power supply 24 is applied to the coil
20 part 23a and an electric current flows through the coil
part 23a. By this situation, the contact part 23b forms
connection, and so an AC current is supplied to the outdoor
unit 1A.
[0040] When the AC current is supplied to the outdoor
25 unit 1A, the outdoor unit 1A performs a normal operation
(Step S201) as in the first embodiment described above.
[0041] While a temperature abnormality caused by
abnormal heat generation in a winding of the DC motor 3
does not occur (NO at Step S202), the outdoor unit 1A
30 performs a normal operation (Step S201).
[0042] When a temperature abnormality caused by the
abnormal heat generation in the winding of the DC motor 3
occurs (YES at Step S202), the temperature protector 5A
16
operates (Step S203), so that the electrical connection
between both ends of the temperature protector 5A is cut
off and the power-supply voltage of the communicationcircuit
power supply 25 applied to the outdoor
communication circuit 14 is cut 5 off (Step S204).
Accordingly, communication is not established between the
outdoor communication circuit 14 and the indoor
communication circuit 17A, and the indoor microcomputer 16A
determines a communication abnormality (Step S205).
10 [0043] Upon determination of the communication
abnormality, the indoor microcomputer 16A executes control
in such a manner that the power-supply voltage of the
relay-driving power supply 24 is not applied to the coil
part 23a, thereby preventing a current from flowing through
15 the coil part 23a. By this control, the contact part 23b
is opened (Step S206), any AC current is not supplied to
the outdoor unit 1A and electric charges cannot be
accumulated in the electrolytic capacitor 9, so that a DC
voltage applied to the DC/DC converter 10 decreases (Step
20 S207).
[0044] When the DC voltage applied to the DC/DC
converter 10 decreases, a DC voltage applied to the motor
driving element 11 also decreases, so that the motor
driving element 11 cannot generate a driving voltage (Step
25 S208) and the DC motor 3 is stopped (Step S209). The DC/DC
converter 10 also becomes unable to generate the low DC
voltage required for the operations of the outdoor
microcomputer 12, the motor driving element 11, and the
outdoor communication circuit 14, and then the outdoor unit
30 1A is stopped.
[0045] When the power supply to the DC motor 3 is
stopped and any current does not flow through the winding
of the DC motor 3, the temperature of the winding of the DC
17
motor 3 decreases, and the temperature protector 5A is
returned to a state where both ends thereof are
electrically connected to each other. If the temperature
protector 5 is a thermal fuse, it is not returned to its
5 original state.
[0046] However, because the power-supply voltage of the
communication-circuit power supply 25 is not generated by
the DC/DC converter 10, the outdoor communication circuit
14 does not become operable and communication is not
10 established between the outdoor communication circuit 14
and the indoor communication circuit 17A even after the
temperature protector 5 is returned to the state where the
both ends of the protector are electrically connected to
each other.
15 [0047] According to the process illustrated in FIG. 5,
when a temperature abnormality caused by abnormal heat
generation in a winding of the DC motor 3 occurs, an AC
current is not supplied to the outdoor unit 1A. Therefore,
even if the motor driving element 11 is short-circuited,
20 any current does not flow to the DC motor 3, and a current
flowing through the DC motor 3 can be cut off.
[0048] According to the present embodiment, the DC motor
3 is not stopped by control of the outdoor microcomputer 12.
Therefore, even if a function of protecting the DC motor 3
25 using a program in the outdoor microcomputer 12 does not
work for some reason, such as a program runaway in the
outdoor microcomputer 12, it is possible to stop the DC
motor 3.
[0049] According to the present embodiment, a voltage
30 applied to both ends of the temperature protector 5A is low,
as compared with that in a configuration in which a path of
an AC current supplied from the AC power supply 7 is cut
off directly by a temperature protector. In general, a
18
component whose rated voltage is lower has a smaller
component size and it is therefore possible to downsize the
temperature protector 5A.
[0050] Although the temperature protector 5A is provided
between the outdoor communication 5 circuit 14 and the
communication-circuit power supply 25 in the present
embodiment, another configuration may be realized in which
a temperature protector is provided on the indoor-outdoor
communication line 26 and is attached to an outer wall, a
10 winding, or the like of the DC motor 3. Also in this case,
when the temperature protector is operated, communication
is no longer established between the outdoor communication
circuit 14 and the indoor communication circuit 17A, and
the indoor microcomputer 16A can determine a communication
15 abnormality, so that identical effects can be obtained.
[0051] The configurations described in the above
embodiments are only examples of the content of the present
invention. The configurations can be combined with other
publicly known techniques, and partially omitted and/or
20 modified without departing from the scope of the present
invention.
Reference Signs List
[0052] 1, 1A outdoor unit, 2, 2A indoor unit, 3 DC
25 motor, 4 outdoor control board, 5 temperature protector,
6 inrush-current prevention circuit, 7 AC power supply, 8
diode bridge, 9 electrolytic capacitor, 10 DC/DC
converter, 11 motor driving element, 12 outdoor
microcomputer, 13 indoor control board, 14 outdoor
30 communication circuit, 15 indoor power-supply circuit, 16
indoor microcomputer, 17 indoor communication circuit, 18
inrush-current prevention relay, 19 PTC, 20a, 23a coil
part, 20b, 23b contact part, 21, 24 relay-driving power
19
supply, 22 outdoor power-supply relay, 25 communicationcircuit
power supply, 26 indoor-outdoor communication line,
100, 100A, 100B air conditioner.
20
We Claim:
1. An air conditioner comprising an indoor unit and an
outdoor unit, wherein the outdoor unit includes:
5 a motor;
a first relay including a first coil part and a first
contact part provided on a supply line of an alternating
current power supply that is a power supply of the outdoor
unit, in which the first contact part is placed in an
10 electrically-disconnected state when any current does not
flow through the first coil part and the first contact part
is placed in an electrically-connected state when a current
flows through the first coil part;
a PTC (Positive Temperature Coefficient) connected in
15 parallel to the first contact part; and
a temperature protector provided on a supply line of a
relay-driving power supply that is a power supply of the
first relay and provided to the motor, which is in an
electrically-connected state when a temperature of the
20 motor is lower than a predetermined temperature, and is
placed in an electrically-disconnected state when the
temperature of the motor reaches a predetermined
temperature or higher.
25 2. The air conditioner according to claim 1, wherein
the motor is a DC (Direct Current) motor, and
the PTC is a PTC thermistor.
3. The air conditioner according to claim 1 or 2, wherein
30 the temperature protector is attached to an outer wall or a
winding of the motor.
4. The air conditioner according to any one of claims 1
21
to 3, wherein the indoor unit includes a second relay that
includes a second coil part and a second contact part
provided on the supply line of the alternating current
power supply that is a power supply of the outdoor unit.
5
5. An air conditioner comprising an indoor unit and an
outdoor unit, wherein
the outdoor unit includes:
a motor;
10 an outdoor communication circuit to communicate with
the indoor unit; and
a temperature protector provided on a supply line of a
communication-circuit power supply that is a power supply
of the outdoor communication circuit and provided to the
15 motor, which is in an electrically-connected state when a
temperature of the motor is lower than a predetermined
temperature, and is in an electrically-disconnected state
when the temperature of the motor reaches a predetermined
temperature or higher, and
20 the indoor unit includes:
a relay including a coil part and a contact part
provided on a supply line of an alternating current power
supply that is a power supply of the outdoor unit, in which
the contact part is placed in an electrically-disconnected
25 state when any current does not flow through the coil part
and the contact part is placed in an electrically-connected
state when a current flows through the coil part;
an indoor communication circuit to communicate with
the outdoor unit; and
30 an indoor microcomputer to control a current not to
flow through the coil part when communication is not
established between the outdoor communication circuit and
22
the indoor communication circuit.