Blower fan prob'

[Cliff Rohrabacher]

I have a blower fan that has a dead capacitor.
The blower fan would merely stutter and not turn over.

The original equipment company (ISKRA) won't sell the capacitors one at a time. However they did say that it had to be 25 Micro Farad and 450 Vac.

I got one from DIGIKEY. It's a blue poly rectangle with 4 solder terminals - the original was a metal canister with two male spade plugs. However it is a 25uf and 450 Vac.

I put it on the fan.
The fan with the new one will turn over - after a while of trying. However, it won't come up to speed.

I am thinking I need a larger capacitor like maybe 500 or 550 Vac.
Any ideas?

[Lee Schierer]

It sounds like your capacitor is too small. Talk to a motor repair shop and they can put you onto the proper size capacitor. The old one should have a rating on it.

[Ken Fitzgerald]

The voltage rating doesn't effect the speed at which the motor comes up. It the safe maximum operating voltage at which the capacitor is capable of working. Voltages over that could possibly damage the capactor.

What you need, IIRC is a electrolytic capacitor. Like Lee said....find a local small motor repair shop. They should have what you need.

[Cliff Rohrabacher]

It sounds like your capacitor is too small. Talk to a motor repair shop and they can put you onto the proper size capacitor. The old one should have a rating on it.

Well it is the same specification set of the original and the manufacturer of the original capacitor (ISKRA) said to make sure that any replacement was 25 MicroFarads at no less than 450 Vac. And it is exactly that.

I wish I had a motor repair house nearby.




The voltage rating doesn't effect the speed at which the motor comes up. It the safe maximum operating voltage at which the capacitor is capable of working. Voltages over that could possibly damage the capactor.

"Voltages [Line voltages] over that" {OR} "Voltages [capacitor rating voltages] over that could possibly damage the capacitor."

I don't know which you mean.



What you need, IIRC is a electrolytic capacitor. Like Lee said....find a local small motor repair shop. They should have what you need.

Hmmm Would that necessarily be a canister?

[Tom Veatch]

"Voltages [Line voltages] over that" {OR} "Voltages [capacitor rating voltages] over that could possibly damage the capacitor."

Voltage applied to the capacitor greater than the voltage rating of the capacitor could damage the capacitor.

The cap needs to rated for a voltage considerably above the supply voltage because when the motor is turned off, the collapsing magnetic field inside the motor can cause a voltage spike that is greater than the supply voltage. That is also why devices intended to switch inductive loads (like motors) are rated not only for supply voltage and amperage but also in terms of HP. And usually the HP rating is the most restrictive.