Any Electrical Engineer Types Out There? SSR vs Electro-Mechanical Relay

[1 Wild R/T]

Ok the story...
Our clothes dryer is 11 years old, last year it had a problem, the heater coils were staying on when ever the dryer was running.....   I found the heater relay contacts had welded themselves shut, unfortunately the relay wasn't a separate component it was part of a board....  I sucked it up & bought a new board for $227.....   And all was right with the world.... Till this week... The points have stuck again...  Not nearly as bad, I tapped the relay & it started working again....  I still have the old board & it has a Tyco relay made in Mexico.... The new board has a  Sanyou relay made in China.... Anyway, a little online research confirms I'm not the only one having trouble with the new board.....  So me being me, I popped the relay off the board & soldered wires onto the board....  And find a stand alone relay Whirlpool uses on more basic model dryer, I ordered it & when it arrives I discover the control side is 48vdc and my relay is 12vdc.... So I'm looking at options & realize I have an industrial SSR with all the specs matching up perfectly... well actually the old relay is 30a 240vac  & this Crydon SSR is 40a 250vac....  Just not sure if an SSR is a good match for an inductive load...... 

Any thoughts? 
Thanks!

[gzig5]

Pretty sure you shouldn't have any problems with the SSR on an inductive load.  My company makes industrial servo drives and we switched to SSR's of various configurations years ago.  Inductive loads, even at 24 VDC are really tough on regular contact relays.  As a matter of fact, I did a test on one of our products and where standard relay was failing at 85,000 cycles our solid state design using a power FET went 13 million cycles and was still going when I got tired of listening to it.  Not likely the designs are the same, but the only time I've seen problems with SSRs is with very low impedance loads, like an SSR driving an SSR and in that case it was a turn on issue not a wear out problem.

[73440]

https://www.arrow.com/en/research-and-events/articles/crydom-solid-state-relays-vs-electromechanical-relays

Not an electrical engineer, just seeing in articles that SSR may require a heat sink or fan .

[1 Wild R/T]

Excellent, confirms what I felt was the case....... The SSR will be running when the dryer is scrapped...  Thanks!   

[1 Wild R/T]

https://www.arrow.com/en/research-and-events/articles/crydom-solid-state-relays-vs-electromechanical-relays

Not an electrical engineer, just seeing in articles that SSR may require a heat sink or fan .

Didn't see this earlier..
you posted at the same time I did....  The new SSR I have has a heat sink...   Right now the dryer is working with a Bosch 5 pin relay which isn't designed for the job but it works... Next week I get it swapped out & post pictures..... Since everyone here wants to know how to fix their dryer.....

[73440]

I have 2 year old washer and dryer and the washer has been a nightmare electronically,I dont even like to turn any knobs or settings anymore as it goes crazy ,  replaced control board and lid lock , so I am expecting dryer issues also.
Always good to know about equipment.

Good to hear about yours having the heat sink , read that in two articles so figured was probably needed.

[71-440]

Like you my dryer went out about 2 months ago. Did a search on you-tube and a guy with the same exact dryer and problem came up. Anyway the dryer is 9 years old and I replaced the board
and its working fine again. 210.00 for the board on Amazon and it was an exact replacement.

Seems you have some knowledge of electrical circuits and glad you got it fixed. It sucks wearing wet clothes......

[1 Wild R/T]

Like you my dryer went out about 2 months ago. Did a search on you-tube and a guy with the same exact dryer and problem came up. Anyway the dryer is 9 years old and I replaced the board
and its working fine again. 210.00 for the board on Amazon and it was an exact replacement.

Seems you have some knowledge of electrical circuits and glad you got it fixed. It sucks wearing wet clothes......

Yeah, my board was an exact replacement too....  $227 through Amazon...   Unfortunately exact replacement didn't equate to exactly the same....  It worked... For 15 months.....     I think this fix will solve that issue..   We'll see what's next.... 

As far as having some knowledge... Just enough to be dangerous... 

[Slotts]

Ah, the age old problem of the EE wanting to design a circuit correctly    and the bean counter wanting to keep the cost down! 

A simple zero cross point circuit is the way to go when controlling a SSL relay. This allows the closing or opening to be delayed until the next zero voltage cross (or very close to it) helping to prevent the relay from arcing, causing failure that has been described. An example of emitted noise when crossing at a high voltage swing in the air would be called thunder.
So, a couple of thyristors were eliminated to keep the cost down.

This graph shows how it works...

Jim

[RUNCHARGER]

Estimated cost saving around 1 cent I bet?

[1 Wild R/T]

So, a couple of thyristors were eliminated to keep the cost down.

Hence the reason the first board lived ten years & the new board lasted 15 months....

The good news, I found info on a Crydom sheet that shows the inductive load can be switched at any time....

[73440]

One more item on washers and maybe dryers , the manufacturer hides the repair an troubleshooting sheets underneath the washer , found mine after the second trouble and was able to use the troubleshooting checklist electronic with the control panel with the found sheet. They want you to call the Maytag repairman.