Terminal corrosion on AC compressors.

[GBDamo]

Been doing some maintenance/service work on AC compressors and one thing that concerns me is the amount of heat at all the various terminals along the start and run circuit.

In brief the the current draw should be anything from ten to twenty amps but I'm often seeing readings 50% higher that this. When viewing the circuit using an FLIR thermal imaging camera there is a lot of excess heat at the spade crimp terminals.

Removing the spades, closing them with pliers and replacing them greatly reduces the heat and resistance but I've noticed all are slightly tarnished.

I'd like to find a none abrasive cleaning solution and a grease that will improve conductivity as well as prevent further corrosion.

I have googled a few products but can't see the sense in reinventing the wheel, i.e. this must be fairly routine in industry and there must be many maintenance sparks out there who do these routinely.

If so can your share some advice or tips for improving the above situation

Thanks

Damion.

 

[GBDamo]

Some of these terminals are coated to improve electrical conductivity,
if this coating is worn then conductivity will be reduced
Have you tried just replacing these terminals with good quality one's.

I'll certainly look to replace any female that becomes slack or loose. Unfortunately the males are fixed on various PCB or other components so cannot be replaced.

 

[dmxtothemax]

Have you tried conductive paint ?

Silver Conductive Pen | Jaycar Electronics - https://www.jaycar.com.au/silver-conductive-pen/p/NS3033

 

[Marvo]

We do quite a lot of HVAC work and from experience the compressor push-on terminals that give overheating problems are usually because the original installer has been ham fisted and causing them to be loose when they were first fitted.

As mentioned above, once this occurs the damage is permanent because they overheat and lose their ability to hold tension even if you compress them again with pliers. If a terminal has become tarnished on both the male and female side due to overheating I'd actually cut the crimp-on terminal off the wire side, clean up the side of the terminal that's fixed and solder it.

 

[gnuuser]

i agree marvo
as long as there is not an excessive amount of vibration once the crimpon terminal is connected you can also paint the connection with a varnish (like nail polish) to prevent air and moisture exposure.
it does withstand heat fairly well.
down side of it is it's a real bear to remove from the terminals
you can also paint over the connection with silicone grease

 

[gnuuser]

the other downside to the varnish would be that it would be difficult to read voltage, and resistance unless you scraped the varnish off.