arc suppressor for relays

do you do this with inductive loads?

I'd try the manufacturer's replacement part first; it could just have been a weak spring or some stuck-half-on that caused arcing.

If the relay ratings can be read, you might consider the gas-filled sealed relays (like, around here, used to be surplused from the aircraft manufactory...). They're very reliable, and it's hard to find one that isn't an improvement to the civilian washing machine parts I've autopsied.

Pressurized gas suppresses arcs quite effectively.

Yes.

At one time you used to be able to get add on soft start SSR's where you connect the relay coil to a terminal dedicated for it. This was to insure the SSR was on (zero crossing) before the coil itself got energized. The turn off did the opposite.. The control off voltage would turn off the relay coil and wait for the contacts to open before it was turned off.

We used to burn up relays every 6 months on a pick of equipment due to the large inductive response the contacts were wire too. This got cycled a lot and a modification was done to stop the arcing. Due to the amp load that is there, the relay still needs to be replaced but it now last at least 5 years or so.

Jamie

Very unlikely to find a 12 V 16 mA coil aircraft relay that will also fit the spot available. I may have found a really small SSR that will fit, but require some fooling around with the leads to fit the board.

Jon

work, and

DATASHEET/CD00000720.pdf

contacts

Oh yeah. Proper snubbers work great.

supressor

and

A "bank" of valves and relays? Usually there are just two, one for cold wat er and one for hot water, not anything complex. You may actually reduce con tact life with the addition of arc suppression. The relay contact materials and operating characteristics such as contact pressure, overtravel, and re lease geometry have been optimized for the weakly inductive solenoid valve type of loading and any modification will most likely reduce contact life. The solenoid loading should only be a few milliamps.

and one for hot water, not anything complex. You may actually reduce contact life with the addition of arc suppression. The relay contact materials and operating characteristics such as contact pressure, overtravel, and release geometry have been optimized for the weakly inductive solenoid valve type of loading and any modification will most likely reduce contact life. The solenoid loading should only be a few milliamps.

I'm sure a VDR across the relay contacts will only serve to enhance contact life not reduce it?

"Mike Perkins"

You may actually reduce contact life with the addition of arc suppression. The relay contact materials and operating characteristics such as contact pressure, overtravel, and release geometry have been optimized for the weakly inductive solenoid valve type of loading and any modification will most likely reduce contact life.

" There is no arc suppression on these relays, and the cold water valve relay is totally shot."

And your mindless hypothesising is UTTER CRAP.

Fuck off.

.... Phil

k, and

water and one for hot water, not anything complex. You may actually reduce contact life with the addition of arc suppression. The relay contact mater ials and operating characteristics such as contact pressure, overtravel, an d release geometry have been optimized for the weakly inductive solenoid va lve type of loading and any modification will most likely reduce contact li fe. The solenoid loading should only be a few milliamps.

Yes, I am sure. If you have ever read some of the research on relay design for the various applications, you would know it is quite sophisticated and empirical. You get different patterns of contact mass transfer dependent up on the type of load characteristics such as inductive versus resistive and inrush. There are design configurations where an unsuppressed inductive loa d results in longer relay life.

Nope, it has 2 valves for cold and hot water, feeding into a manifold. Then, there are 4 more, that send the water straight to the basket, or to the detergent tank, the bleach tank or the softener tank, so these solutions are added at the right time in the cycle. Yeah, way too complicated for sure. I think there may be a couple more valves down in the bowels of the machine to switch the pump lines around (maybe not). Also, there's a door lock solenoid. There are also relays for the water heater and the circulate and drain pumps. So, a hell of a lot of relays in there. Also an IRAMS module for the direct drive basket motor.

I can't imagine a properly designed arc suppressor making things worse, this machine is only FOUR years old. If I didn't know how to fix this, it would be $275 for the entire module plus a service call every 4 years, that would be about $500 I guess. Quite a racket Whirlpool has here!

Jon

OK, I looked up the specific relay by part number, and the data sheet does not even GIVE a rating for inductive load, they only give a resistive load rating! Amazing! Who designs this crap? I'll bet they torture tested it and knew it would last past the warranty, and who cares beyond that? Looking on fixya and similar web sites, it seems this failure is a VERY common problem on the washers using this control module. One user reported it started this failure mode withing a couple weeks of purchase.

Jon

Have you measured the solenoid? Those /are/ mostly resistive, usually several K-ohms. The problem is most likely poor quality control/ design on the relays.

uce

If you're not seeing charred bits and pieces in the relay housing then arc suppression is not the answer. That machine sounds like a nightmare. So muc h for modern electronics being an improvement over the cam-encoded mechanic al switch controls that would typically last 30 years before they even thou ght about giving up.