leccy question

[newspark2]

Hi, Iam a gas eng with a tech question.

A boiler fan resistance measures 44ohms, connected to a 230v supply. What current will it pull from the mains.

TIA.

 

[adnarim]

5.2A,but sounds a bit high,what kind of boiler is it domestic/industrial? check plate on fan motor for FLC(full load current cheers

 

[sivoodoo]

I=V/R therfore 230/44 = 5.2272

 

[Carter]

Any start capacitors in the motor cct?

 

[Shakey]

Hi, Iam a gas eng with a tech question.

A boiler fan resistance measures 44ohms, connected to a 230v supply. What current will it pull from the mains.

TIA.

well theoretically it would be 5 amps, but you are talking about resistance - does that mean you have measured with a meter?

problem is you see, that is 'cold' DC resistance; when power is applied, we talk about impedence, which is a different ball game. Without getting into a technical lesson, there such factors as BackEMF, mutual induction,hysteris losses,inductive reactance etc etc that affect the (ac)'resistance' or impedence. This why on an ac component, the resistance is rarely given, its rating (in Watts) is given, as this is a product of impedence anyway.

 

[Jurassic Spark]

Are you sure the fan's connected to the mains? I would have thought the fan, along with the gas valve and such would be controlled from the circuit board which is usually in the 24V region.