jaytee
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Hi, hope everyone is enjoying Easter!
I have boon looking for an induction hob recently and found one on ebay for £25 and close by so I bought it, yay!. It was purchased as defective, its a 5 sone hob and the two left zones did not power up. A bit of research before purchase shows there were separate circuitry for the left, middle and right zones.
On disassembly I found a blown WYO4N7 safety capacitor in the initial power handling PCB. On removal I also found burnt out tracking on the underside of the module. As the 3 sets have the same compoennts I swapped the PCB assembly from the right side to the left and it is working fine so the cause of the failure was the capacitor.
On looking at the good PCB there is no fuse fitted but there is a thinned section of PCB which is the weak point and appears to be designed to act as a fusable section. This is not as expected because I have seen catastrophic failures of PCB's where carbon has continued to conduct the mains.
The hob is rated at 10,800W total and the two zones involved are rated at 4kW. This infers that up to 17 amps is required. The thinned PCB track is approx .5mm wide and 1mm long, there are two in series.
There is no other electrical path and the full current flows through the two sections. I don't understand how this can work but clearly it did before the cap failed.
Could there be something funny going on with volts and current phase so the effective power is much lower? The zones are resistive, I don't see how they would be any different to a halogen load unless the presence of the pan makes the load inductive?
Does anyone have any thought on how 4kW can go through the tiny tracks, and how can this be repaired? some 13A fuse wire?
I have boon looking for an induction hob recently and found one on ebay for £25 and close by so I bought it, yay!. It was purchased as defective, its a 5 sone hob and the two left zones did not power up. A bit of research before purchase shows there were separate circuitry for the left, middle and right zones.
On disassembly I found a blown WYO4N7 safety capacitor in the initial power handling PCB. On removal I also found burnt out tracking on the underside of the module. As the 3 sets have the same compoennts I swapped the PCB assembly from the right side to the left and it is working fine so the cause of the failure was the capacitor.
On looking at the good PCB there is no fuse fitted but there is a thinned section of PCB which is the weak point and appears to be designed to act as a fusable section. This is not as expected because I have seen catastrophic failures of PCB's where carbon has continued to conduct the mains.
The hob is rated at 10,800W total and the two zones involved are rated at 4kW. This infers that up to 17 amps is required. The thinned PCB track is approx .5mm wide and 1mm long, there are two in series.
There is no other electrical path and the full current flows through the two sections. I don't understand how this can work but clearly it did before the cap failed.
Could there be something funny going on with volts and current phase so the effective power is much lower? The zones are resistive, I don't see how they would be any different to a halogen load unless the presence of the pan makes the load inductive?
Does anyone have any thought on how 4kW can go through the tiny tracks, and how can this be repaired? some 13A fuse wire?