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Components and Circuits For discussions about component types, alternatives and availability, circuit configurations and modifications etc. Discussions here should be of a general nature and not about specific sets.

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Old 12th Jan 2022, 11:29 pm   #41
klugardo
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Default Re: Blown capacitor. Actually an MOV.

hey wave solder.

thank you looks like i need a AP

thank you
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Old 12th Jan 2022, 11:37 pm   #42
bigfathairyvika
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Default Re: Blown capacitor. Actually an MOV.

Just a thought, what voltage is the supply?
I ask because the MOVs are rated at 175v so I would expect the supply to be less than this.
Could it be that you have a 110v controller and have connected it to a 220v supply.
This would be fairly easy to do where there are several 110v rails , which would likely be two separate phases and usually used to get 220v. Which is quite common in the US.

Although, if you have previously had the controller working and it has only recently failed, then ignore the above.
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Old 13th Jan 2022, 12:14 am   #43
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Default Re: Blown capacitor. Actually an MOV.

If the MOV is across the 120V then it's probably just unfortunate and a new one will fix it. But I suspect being an induction cooktop (hob) then it will have the option to use a 2-phase (4 prong) supply. If you get the mains wiring wrong (eg one hot and the neutral crossed) then you may be putting 240V into one of the pair of 120V input lines hence the blown MOV.

For the uninitiated, unlike the UK some US houses are supplied via a 240V centre-tapped 120-0-120 pole transformer to give both 120V (2/3 prong) and 240V (4 prong) outlets.

UK-spec 240V induction hobs often come with 2-phase inlet terminal blocks with a brass jumper normally connecting the two live terminals.
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Old 13th Jan 2022, 12:46 am   #44
klugardo
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Default Re: Blown capacitor. Actually an MOV.

i cant tell you why the mov's are 175

this is a 240v unit

there are only 2 varistors on the board.

for sure they are 175L20

like i said it worked then i unplugged it.
when i plugged back in BOOM.

I did call and was told its a 40 amp unit so

i will remove the 50 amp circuit breaker and replace with a 40.

only thing i am worried about is i have 10 gauge wire which is rated for 50amp

i hope the larger gauge isnt whats allowing a surge and more voltage to hit the unit.
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Old 13th Jan 2022, 12:47 am   #45
klugardo
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Default Re: Blown capacitor. Actually an MOV.

mcmurdo

its just a 2 wire unit with ground.

white black and ground
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Old 13th Jan 2022, 1:26 am   #46
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Default Re: Blown capacitor. Actually an MOV.

Is this a wind up?
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Old 13th Jan 2022, 5:41 am   #47
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Default Re: Blown capacitor. Actually an MOV.

Remember that in the USA, heavy domestic appliances are fed a two-phase supply 120-0-120.

So a 175v MOV from each side to neutral would not seem unreasonable. But if so, there is something extra at play here, like a missing neutral and an asymmetric load.

This cooker is trying to tell the owner something, and that something could be a matter of genuine danger to life or limb.

This may be a case where qualified help needs to be called in. I'm not confident that the OP has sufficient experience to be able to spot a dangerous condition.

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Old 13th Jan 2022, 8:27 am   #48
markfff
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Default Re: Blown capacitor. Actually an MOV.

Quote:
Originally Posted by klugardo View Post
its just a 2 wire unit with ground.
white black and ground
It's still most likely to be a split phase appliance, 120-0-120 as David says. Often they are (but shouldn't be) wired with ground doubling as neutral. Older houses tend to be wired this way. So, if your ground/neutral is open or has a poor connection, the two 120V phases will become unbalanced causing the voltage on one to be too high (possibly why the MOV blew) and the other too low.
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Old 13th Jan 2022, 12:49 pm   #49
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Default Re: Blown capacitor. Actually an MOV.

I've just read the installation instructions, (its a halogen rather than induction BTW) and it confirms it only requires 208-240V 2-wire plus ground, and states no neutral is required.

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Old 13th Jan 2022, 10:22 pm   #50
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Default Re: Blown capacitor. Actually an MOV.

Quote:
Originally Posted by McMurdo View Post
I've just read the installation instructions, (its a halogen rather than induction BTW) and it confirms it only requires 208-240V 2-wire plus ground, and states no neutral is required.
Even if the cooktop doesn't use a neutral, the 175V MOV's are probably connected between each phase and ground, so if the ground is floating, that part of the circuit could become unbalanced causing one of the the MOV's to see a higher voltage than it's rated for.
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Old 14th Jan 2022, 12:11 am   #51
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Default Re: Blown capacitor. Actually an MOV.

If anyone's interested, this is what the typical residential wiring looks like in the US. Houses are fed power from a 240V center tapped transformer. The line from the center tap is grounded to earth near the breaker panel and connects to the ground and neutral busses at one point in the panel. After that, ground and neutral wires go their separate ways.

Lights and wall receptacles as well as low power built in devices, like bathroom fans, are fed from one of the two 120 Volt circuits. High powered devices are wired for 240V across both 120V circuits.
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