1. Title of the invention
Portable rig for pre-installation checks of Relays.
2. Field of invention
The invention is considered for the field of electrical ground support equipment. It is designed to check the functionality of relays before they are installed on aircraft.
3. Use of invention
. Electromechanical relays are prominently used for switching signáis and electric power. The Pre-installation (Pl) check is the final inspection that every component (including relays) goes through before being installed on the aircraft. Pl check is carried out on every relay to verify the following design specifications of the relay:
a) Pick-up voltage (mínimum voltage required to cióse the relay's contacts)
b) Drop-out voltage (mínimum voltage below which relay's contacts open).
c) Contact continuity (closing and opening of relay contacts as per specification)
d) Voltage drop across the contacts (voltage drop measured across relay contacts when they are carrying their rated current)
The following relays undergo Pl checks:
i. 2 Pole 5 Ampere relay (henceforth named as TR1)
¡i. 4 Pole 5 Ampere relay (henceforth named as TR2)
iii. 2 Pole 10 Ampere relay (henceforth named as TR3)
iv. 4 Pole 10 Ampere relay (henceforth named as TR4)
v. 6 Pole 10 Ampere relay (henceforth named as TR5)
vi. 2 Pole 2.5 Ampere Time Delay relay (henceforth named as TR6)
vii. 2 Pole 10 Ampere Latched relay (henceforth named as TR7)

This portable rig for pre-installation checks brings down the turn-around time (time elapsed between dispatch of relay for Pl check and obtaining the Pl check results), transit time (time taken for transporting the relay to the Pl check facility) and human error (error during measurement, connecting wires and considerably by simplifying the process of testing to just three steps:
Step 1: Mount relay to be tested on the socket
Step 2: Tests for Pick-up voltage, drop-out voltage, contact continuity and voltage drop across the contacts
Step 3: Dismount relay from the socket Prior art
A typical Pl check activity consists of manually assembling the test setup. Connections are wired manually for continuity and millivolt drop test. Tests for Pick-up voltage, drop-out voltage, contact continuity and voltage drop across the contacts are carried out for each relay. The connections are re-wired after every test depending on the type of relay, current rating of relay and requirement of trigger/latch voltage to the relay coil.
Draw backs of prior art
The absence of fabricated wiring leads to unnecessary time spent carrying out the wiring for each test. Absence of hard mounted sockets and connectors results in unreliable electrical connections and errors in measurement of voltage/continuity.
Comparison between prior art and present invention
The rig contains wiring to provide connections for the types of relays mentioned in section 3. The wiring configuration is selected through an electrical switch, depending on the type of relay. Standard sockets for mounting relays are provided and the entire test setup is assembled in a metal enclosure. Henee, this invention improves aecuracy during Pl checks and reduces human effort for testing the relays.
Aim of the invention
i. To improve aecuracy of measurement and reduce time taken during Pl checks ii. To provide a rig that standardizes the Pl check process for the relays iii. To provide a portable test rig for the relay Pl check

Summary of the present invention
This invention provides a single platform to test the functionality of relays listed in section 3, which are used on the aircraft. Prior method of manually wiring for each relay is replaced with selecting the relay and type of test by setting the switch position. Provisions are made to mount the relay to be tested. Electrical termináis are available to measure the test parameters of the relays. Switches are provided to select the type of relay and type of test as mentioned in section 3. Miniature circuit breakers are used for protection from electrical short circuit in the wiring and overloading of relay during the Pl check.
Brief description of drawings
Fig.l : A block diagram of the prior method of relay Pl check
Fig.2 : Block diagram of the relay testing according to the invention
Fig.3 : Functional block diagram of the Trigger/Latch switch
Fig.4 : Functional block diagram of the Continuity test switch
Fig.5 : Functional block diagram of the Millivolt drop test switch
Fig.6 : Mechanical interface of the invention
Statement of invention
The portable rig for Pre-lnstallation (Pl) checks has been designed to overeóme the labor-intensive procedure of manually wiring connections for each relay under test and to select a different wiring schematic for each type of relay. According to the invention, both of these laborious procedures are not required when operating the rig. The rig has been approved by the in-house Quality Assurance department, taking into account the reduction in human effort with a simultaneous improvement in efficieney of the Pl check process. It is being used extensively for carrying out the Pl check of relays.
Detailed description of invention
The prior method of Pl check as shown in Fig.l comprised of the following requirements: power supply termináis 1; circuit breaker 2; relay with manual wiring 3; manually connect wiring for continuity test 6; manually apply trigger/latch voltage 7; manual measurement at each terminal 8; manually connect wiring for millivolt drop test 4; variable load for passing the load current through the relay 5;
The rig according to this invention, as shown in Fig.2, comprises: power supply termináis la; circuit breaker 2a; relay sockets for mounting relays 3a; trigger/latch switch to apply voltage to respective coil of relay 4a; continuity test switch to select the corresponding wiring for the relay 5a; variable load to achieve the rated current capacity 6a; Millivolt drop test switch to select the corresponding wiring for the relay 7a;
The trigger/latch switch (4a) as shown in Fig.3 selects the wiring to apply the trigger/latch voltage to the relay under test. The continuity test switch (5a) as shown in Fig.4 selects the wiring to apply voltage to the relay coil and enable continuity measurements at the contacts of the relay. The millivolt drop test switch (7a) as shown in Fig.5 passes the rated current through the relay and selects the wiring required for measuring the millivolt drop across the relay contacts.
The mechanical interface of the invention is depicted in Fig.6. Each relay socket named as TR1, TR2, TR3, TR4, TR5, TR6 and TR7 can be mounted only with the designated typé of relay, which streamlines the testing process for the operator. Function select sw (SI) is a switch used to select between 'off, 'continuity' and 'millivolt' test by toggling the switch to the corresponding position. Millivolt test (S2) is a switch used to select the type of relay between '2 Pole','4 Pole' or '6 Pole' by toggling the switch to the corresponding position. Trigger (S3) is a switch used to apply the trigger voltage to the type of relay 'TR6' and by toggling the switch between 'trigger' and 'off. Latch (S4) is a switch used to apply latching voltage to type of relay 'TR7' by toggling the switch between 'Y1-Y2', 'Off and 'X1-X2'.
In Fig.6, electrical overload protection is provided by the miniature circuit breakers CB1, CB2, CB3, CB4, CB5, CB6, CB7 and CB8. 'Terminal-1', 'Terminal-2' and 'Terminal-3' are the electrical termináis which allow measurement of voltage/continuity at the relay contact ends. 'POWER ON' is a light emitting diode that glows to indícate the availability of input power supply. 'LOAD ON' is a light emitting diode that glows to indícate that the voltage is available at the variable load. Pl(+ve) and Pl(-ve) are termináis to connect the input power supply for testing the relays. P2(+ve) and P2(-ve) are termináis to connect the variable load, and the Ammeter is connected to measure the load current.

Claims
We claim that
a) A rig to carry out Pre-lnstallation (Pl) checks of relays, in which the relay is mounted for checking the Pick-up voltage, Drop-out voltage, Contact continuity and Voltage drop across the relay contacts.

b) A rig for Pl check of relays as claimed in claim 1, wherein the rig comprises of Relay socket for mountjng the relay to be tested

c) A rig for Pl check of relays as claimed in claim 1, wherein the rig comprises of Continuity test switch to select the wiring for continuity check of relay /

d) A rig for Pl check of relays as claimed in claim 1, wherein the rig comprises of Trigger switch to apply the trigger voltage to the Time Delay relay

e) A rig for Pl check of relays as claimed in claim 1, wherein the rig comprises of Latch switch to apply the latching voltage to the Latched relay

f) A portable rig for Pl check of relays as claimed in claim 1, wherein the rig comprises of Millivolt drop switch to select the wiring for measuring the millivolt drop across the relay's contacts