Simple 240vac power switch

[Julianh]

Hi all,

Could anyone help me with a very simple circuit?

I have a large 240v ac fan, that needs to be switched on if a supply is detected at either of two sources. The large fan creates an air flow, dispersing the heat from the heater more evenly, it is also used to push the air the to the extractor fan, when either of them is switched on. If both are on, it also needs to run.

One source is a mains, 240v ac, heater, the other is an humidity controlled extractor fan. I thought the easiest way would be to use a couple of relays, with the coils linked to the sources. This works fine with the heater, but not with the extractor fan.

With the heater, I tapped into the mains supply to it, as it's on a timer / thermostatic switch. Easy.

With the extractor fan, I tapped into the supply of the fan itself, mains, but after the control circuit. It's an all in one device with built in humidity circuit. This doesn't work, i tested the fan's supply it's 240vac, but the relay buzzes when this switches off. So the control circuits output may be 240v ac, but it's not happy running the coil of the relay.

The diagram is below.

I need a simple circuit that detects a mains voltage on one of two inputs, and switches an isolated, separate, 240v ac, 1 amp supply.

Thanks for your help

Julian

 

[tpetar]

Hi all,

Could anyone help me with a very simple circuit?

I have a large 240v ac fan, that needs to be switched on if a supply is detected at either of two sources. The large fan creates an air flow, dispersing the heat from the heater more evenly, it is also used to push the air the to the extractor fan, when either of them is switched on. If both are on, it also needs to run.

One source is a mains, 240v ac, heater, the other is an humidity controlled extractor fan. I thought the easiest way would be to use a couple of relays, with the coils linked to the sources. This works fine with the heater, but not with the extractor fan.

With the heater, I tapped into the mains supply to it, as it's on a timer / thermostatic switch. Easy.

With the extractor fan, I tapped into the supply of the fan itself, mains, but after the control circuit. It's an all in one device with built in humidity circuit. This doesn't work, i tested the fan's supply it's 240vac, but the relay buzzes when this switches off. So the control circuits output may be 240v ac, but it's not happy running the coil of the relay.

The diagram is below.

I need a simple circuit that detects a mains voltage on one of two inputs, and switches an isolated, separate, 240v ac, 1 amp supply.

Thanks for your help

Julian

Hi Julian and Welcome to EDABoard,

What circuit controls relays coils ? Solution can be in that segment.

Other solutions can be to use optocoupler for sensing mains voltage presence, or usage of contactors with coil on 220V,....

Just to ask, that fan uses different mains phase ?


Best regards,
Peter

 

[Julianh]

Hi Julian and Welcome to EDABoard,

What circuit controls relays coils ? Solution can be in that segment.

Other solutions can be to use optocoupler for sensing mains voltage presence, or usage of contactors with coil on 220V,....

Just to ask, that fan uses different mains phase ?


Best regards,
Peter

Thanks Peter,

The first relay coil is attached directly to the mains output from the heater's thermostatic timer, in parallel to the heater itself.

The second relays coil is attached, in parallel, to the feed for the humidity fan, after its control circuit.

It's all single phase, running in a shed!.

I hope this helps, please ask if you need anything else, I thought of an optocoupler, but I haven't designed any circuits for 10 years!

Thanks

Yours

Julian

 

[tpetar]

Relay coils are for 220V AC ?


Best regards,
Peter

 

[Julianh]

The coils are 240v ac

- - - Updated - - -

Thanks

Julian

 

[tpetar]

The coils are 240v ac

- - - Updated - - -

Thanks

Julian

Then one of solution can be with optotriac and triac.


Best regards,
Peter

 

[Julianh]

Then one of solution can be with optotriac and triac.


Best regards,
Peter

Thanks Peter,

Any chance you could PM / email me with a simple diagram?

Thanks

Julian