GE Electro mechanical Relay

Hello,

I am trying to determine the settings on an old GE electromechanical relay. There are three settings, pickup, time dial, INST. The time dial and INST values seem fairly straight forward. The pickup values howver show a plate with screws (see attached picture). How are you to determine the settings? Is it based on the placement of screws or is there a plate behind the cover that needs to be seen? Thanks in advance for any help or advice. 

Been quite a while since I've seen/used one of these. I'd have to research it more but perhaps some others here might be able to chime in:

@mudpuppy, @Flyer_PE, @Dark Knight

Looks like the relay is an IAC53 or 54 from the instruction manual referenced.  The placement of the screws determines the tap setting for the relay.  A simple google search will get you a pdf of the manual (GEK-34054).

I think I can see the pickup tap screw in the picture, under the reflection of your glasses.  There's often numbers written next to the holes to indicate the pickup tap setting associated with each screw hole.

The time dial can be read off the dial, but the numbers on the dial are notoriously inaccurate.  It's best to run some test current through the relay and measure the trip time and then interpolate the time dial from a Time-Current curve in the relay manual (or better yet, use a software program such as E-TAP, Aspen or CAPE to back-calculate the time dial).

The INST setting is also best found out by running test current through the relay.  Just ramp current up until it trips.

Thanks for the help guys. I was able to get it figured it out. We were replacing this old thing with a new SEL-351.