Potential relay Part 1

If you are a homeowner looking to repair your own appliance, understand that the voltages can be lethal, the fuels are highly flammable and high pressures are used. Know your limits.

[rabidpiglet]

This video helps a lot to get a better understanding of what is happening and how - at a pretty basic level - just what I was looking for to start figuring this stuff out! Off to Part 2!

[michaelmace]

I'm very thankful for all the work you put into these videos trying to help others.

[bernardocisneros]

When this relay energizes, it opens the contacts between termnal 1 and 2 thereby disconnecting the start capacitor from the circuit, but it doesn't "shut off" or remove the start winding from the circuit. The start winding continous to help rotate the rotor but with less torque since the start capacitor is no longer in the circuit.

[Straycurrent]

Good close-ups -- I've never cut one apart and taken such a close look.  The #20 stat wire in the comparison photo looks like a framing nail. 

[coilsmoke]

Reminds me of old school automobile voltage regulators before solid state came along. Very informative, Thanx...

[wadibeed]

Potential relay works as open delay by using EMF but takes the voltage from motor at starting up time, not directly from the main power.

[alchemy]

So when this thing is sitting on the table there should be continuity between 1 and 3? or 2 and 3? or 1 and 2?
And when this thing opens there should be continuity between what terminals.
I seem to have a 4 terminal deal here. There is continuity between 1 and 2 and no other continuity right now. So I am assuming 1 goes to the capacitor. 2 goes to S part of the compressor and 3 goes to C. and 4 goes..? Maybe I don't need to use it or use on a little 4 uF run capacitor.... or leave it out and see what happens? It seems to be normally open between 3 and 4
I got this thing out of them motel window units and I figured the compressor works and I will just turn it into a little air compressor. I do run it manually using the capacitor but I figure I will just get a little sophisticated.

[arneyjeff]

Informative video!  Thanks.  When, if ever should you use a start capacitor (cap and relay separate, or super boost)  on a scroll compressor?

[robertst-denis]

i have kitchenaid model is YKBRS21KAW00 my problem is .if the temp control is off!! the defrost timer is making noise and advance, evap fan is running freezer is cool and compressor wont start.

but if the temp control is on!!! the compressor start ok freezer stay cool, but defrost timer is not making that noise and does not move a bit, evap fan won't start at all and inside the fridge part its hot no air coming from the vent in fridge. .

the light in fridge and freezer stop working and there is a small switch for uses less energy if flip one side and flip on other side is for reduces exterior moisture the light does not come on either on the switch. not to sure what this switch do but din't seem to make a difference in the pass but i know that light was coming on if it was flip on before .

could it be the relay that isshort out or something ? any suggestion of what can be wrong ?

I change the defrost timer last year and i change the evap fan too at the same time !.something is running backward but not sure what could do it ...
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[jollyscaria]

Starting relay starting relayis usedfor csr cmprssor motortodisconnect startting capaciter after startingthe motor the the starting reayuedin airconditio is called voltagereay ..potential relay or magnetic reay.theopeeationofthistype ofthisreay depends upontheincreaseof voltageatthe comprssor terminals after startig ...) rely potshio resly enxig lw lw power roing pin r string point comon over coil enges potshio rrly using ok

[Impedancenetwork]

There is nothing special about this "potential relay" it is a relay just like all other electro-mechanical relays. Your explanation about why the wire is so small is incorrect. It is not because, "you don't want that thing energized until you get a very high voltage." That wire is small because you need a specific number of turns of wire to create enough force to pull the armature down. You can't physically put big wire in there because it's a tiny relay. All small relays have small gauge wire to create the coil. The number of turns in this coil is determined by the amount of force needed to pull the armature down. This is how ALL relays work. Potential relays are usually adjustable relays such that you can vary the potential (potential is just another word for voltage) threshold that causes them to energize. So lets say I wanted a relay that detected a 75Vrms rise in potential on a circuit normally operating on 26 VAC rms. I would buy a potential relay such that it would only energize at that voltage and would latch once energize causing a siren to go off and a beacon warning someone of an abnormal condition. What is happening is that some engineer used basic electromagnet theory to determine the voltage that would appear across the start winding once this motor got near synchronous speed then he specified a relay that would energize at that particular voltage plus or minus 10%. Once that relay energizes it magically takes the start capacitor out of the circuit. This relay maybe called a potential relay, but it really isn't strictly speaking. This relay is looking for something like oh 300 or 400 VAC to energize. You can get online and buy a relay with that coil rating and use it for the starting the motor. You don't need a potential relay and this isn't a potential relay any more than any other relay is a potential relay. All relays are technically potential relays because they need a potential difference across their coil to energize. And since that is the case this relay isn't special in any way. The small wire you see will be that small on ALL small relays. It's not small gauge wire in this relay because it has some magical properties. All relays have tiny wire like this in them. I hope nobody takes this video too seriously and goes around to their buddies in the shop saying, "oh man go watch this video. It explains those potential relays." Don't listen to GFM's explanation as to why this potential relay works. This relay works like ALL relays. It simply comes on because the coil is looking for a great enough voltage to energize. That is what all relays are looking for. Once the potential difference becomes great enough it will energize. This can be determined experimentally with a fast Peak responding meter like a Fluke 689 or an digital storage oscilloscope. Once you determine that you simply go buy a relay with that coil voltage rating and Voila (say it like walla) you have a potential relay that you can use in this circuit. I need to make my own video on how this stuff works. I don't want all you HVAC guys to go around repeating what this guys says.