arc suppressor for relays

On 06/10/2012 13:02, bloggs.fredbloggs.fred@gmail.com wrote:
> On Wednesday, October 3, 2012 3:23:31 PM UTC-4, Jon Elson wrote:
>> We have one of those $1K high efficiency washing machines. It does work, and
>>
>> clearly reduced our water and gas bill, so I'm not complaining.
>>
>>
>>
>> Lately, it has been getting "slow fill" errors, and I tried a bunch
>>
>> of typical stuff before finding the REAL problem.  They have a bank
>>
>> of electromechanical relays to operate a bank of solenoid water valves.
>>
>> There is no arc suppression on these relays, and the cold water valve
>>
>> relay is totally shot.  I have replacement relays on order, but want to
>>
>> add arc suppression to prolong the life of the relays.
>>
>
> A "bank" of valves and relays? Usually there are just two, one for cold water 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
Video Solutions Ltd
www.videosolutions.ltd.uk

"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."


** Time for a reality check  -  sunshine.

 And your mindless hypothesising is  UTTER  CRAP.

 Fuck off.


....  Phil

On Saturday, October 6, 2012 8:05:42 AM UTC-4, Mike Perkins wrote:
> On 06/10/2012 13:02, bloggs.fredbloggs.fred@gmail.com wrote:
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> > On Wednesday, October 3, 2012 3:23:31 PM UTC-4, Jon Elson wrote:
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> >> We have one of those $1K high efficiency washing machines. It does wor=
k, and
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> >>
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> >> clearly reduced our water and gas bill, so I'm not complaining.
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> >>
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> >>
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> >>
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> >> Lately, it has been getting "slow fill" errors, and I tried a bunch
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> >>
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> >> of typical stuff before finding the REAL problem.  They have a bank
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> >>
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> >> of electromechanical relays to operate a bank of solenoid water valves=
.
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> >>
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> >> There is no arc suppression on these relays, and the cold water valve
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> >>
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> >> relay is totally shot.  I have replacement relays on order, but want t=
o
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> >>
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> >> add arc suppression to prolong the life of the relays.
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> >>
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> >
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> > A "bank" of valves and relays? Usually there are just two, one for cold=
 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.
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> >
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> I'm sure a VDR across the relay contacts will only serve to enhance=20
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> contact life not reduce it?
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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.

bloggs.fredbloggs.fred@gmail.com wrote:


> A "bank" of valves and relays? Usually there are just two, one for cold
> water 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.
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

bloggs.fredbloggs.fred@gmail.com wrote:


> 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
> upon the type of load characteristics such as inductive versus resistive
> and inrush. There are design configurations where an unsuppressed
> inductive load results in longer relay life.

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

On Monday, October 8, 2012 4:37:46 PM UTC-4, Jon Elson wrote:
> bloggs.fredbloggs.fred@gmail.com wrote:
> 
> 
> 
> 
> 
> > 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
> 
> > upon the type of load characteristics such as inductive versus resistive
> 
> > and inrush. There are design configurations where an unsuppressed
> 
> > inductive load results in longer relay life.
> 
> 
> 
> 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.

On Monday, October 8, 2012 4:28:46 PM UTC-4, Jon Elson wrote:
> bloggs.fredbloggs.fred@gmail.com wrote:
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> > A "bank" of valves and relays? Usually there are just two, one for cold
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> > water and one for hot water, not anything complex. You may actually red=
uce
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> > contact life with the addition of arc suppression. The relay contact
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> > materials and operating characteristics such as contact pressure,
>=20
> > overtravel, and release geometry have been optimized for the weakly
>=20
> > inductive solenoid valve type of loading and any modification will most
>=20
> > likely reduce contact life. The solenoid loading should only be a few
>=20
> > milliamps.
>=20
> Nope, it has 2 valves for cold and hot water, feeding into a manifold.
>=20
> Then, there are 4 more, that send the water straight to the basket,
>=20
> or to the detergent tank, the bleach tank or the softener tank, so these
>=20
> solutions are added at the right time in the cycle.  Yeah, way too
>=20
> complicated for sure.  I think there may be a couple more valves
>=20
> down in the bowels of the machine to switch the pump lines around
>=20
> (maybe not).  Also, there's a door lock solenoid.
>=20
> There are also relays for the water heater and the circulate and drain
>=20
> pumps.  So, a hell of a lot of relays in there.  Also an IRAMS
>=20
> module for the direct drive basket motor.
>=20
>=20
>=20
> I can't imagine a properly designed arc suppressor making things
>=20
> worse, this machine is only FOUR years old.  If I didn't know how to
>=20
> fix this, it would be $275 for the entire module plus a service call
>=20
> every 4 years, that would be about $500 I guess.  Quite a racket
>=20
> Whirlpool has here!
>=20
>=20
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> Jon

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.