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The fan did have a connection to earth as it was sat on its mounting bracket on the metal inside of the top of the oven.
Something I never measured was L – Fan body (Earth) 30 Ohms, N – Fan body 65 Ohms, L – N 100 Ohms. Still have old style fuses.
So why does the fan draw more current when connected to the output of the timer pcb as there is more resistance or is the 100 ohm resistor in parallel with the 30 Ohm L – E?OK, I thought I’d try the original fan motor with the 100 ohm resistor on the bench, ran ok and the resistor didn’t glow, current drawn was 0.25A. Connected to the timer pcb and it started up straight away (which shouldn’t happen) and it drew nearly 1A, resistor hot.
This lead me to believe it was the timer pcb that was at fault. New motor had arrived £180 from Radio Spares. Ordered new timer pcb from espares £30. Swooped timer pcb’s and connected old motor and it ran straight away drawing 1A. Swooped old motor for new motor and it didn’t run until you turned on one of the ovens or grill – correct operation. Swooped new timer pcb for old timer pcb and it still worked correctly!
So basically it was the motor that was faulty.What I cannot understand is why the old motor appears to work ok when NOT connected to the timer pcb and draws more current and runs all the time when connected to the timer pcb.
Anyone any thoughts, (both motors had the same resistance and I don’t have a way of measuring inductance)?
Measured resistance of fan – 150 Ohm, from the current stated on fan it should be 742 Ohms.
Quoted price for a rewind – not less than £300.
The nearest EBM PAPST fan appears to be a R2S175-AB56-01 and the cheapest I can find it is £143.62 + carriage!
Anyone know of a cheaper equivalent or I’ll have to buy a new oven.Thanks electronic, what is the source of your information.
The cooling fan on the oven had stopped and it was found that the series resistor had broken. Replaced the resistor and it lit up like a 100W bulb. I take it that the resistor is acting like a fuse where when the motor draws too much current the resistor exceeds it’s rated wattage and breaks?
I replaced the resister with two 10W 220ohm resistors in parallel so would have had 20W current rating but these have broken as too hot. The motor is rated as 0.310A 70W.
Any idea what the timer pcb does, does it just switch the negative to the other side of the motor?
