extractor fan with Transformer

Hi Guys ,
just a question about an icon 30 12volt bathroom fan .Mine shook itself to bits and stopped working .The impellar snapped off its mountings .I have the same as a replacement under warranty .I have changed them over but the new one doesnt kick in .It has a humidity module which switches fan on when moisture is detected in th air .

I have power to the module but it only reads as 4 volts .
My question is ,does this mean the transformer is goosed as well .I did get a new one with the fan but was not going to fit it if the old one is ok as it is buried in the floor upstairs above the downstairs bathroom so means lifting carpet .floor boards etc .

So should the power be reading 12 volts at the module in th fan where the power cable is connected .(I am thinking it should )but i need it confirming before I start a major job of lifting floors etc .

Many Thanks for your help .
Regards
Rob.

P.s the fan was making a right racket before giving up altogether ,would this have put strain on the transformer ??
Tried to give as much info as possible so apols for the long winded short question !!

Yes the fan is designed to have 12 Volts DC available (on load) at the 0 and +12 V terminals. What are you using to measure the voltage? I assume a multimeter set to DC VOLTS? If that is the case then it sounds like the stalled motor overloaded the power supply output. You will need to change it.

sparkticus said:

Yes the fan is designed to have 12 Volts DC available (on load) at the 0 and +12 V terminals. What are you using to measure the voltage? I assume a multimeter set to DC VOLTS? If that is the case then it sounds like the stalled motor overloaded the power supply output. You will need to change it.

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Thanks sparkticus .Thats the sort of answer I understand and I will change the transformer to hopefully make the fan work again
Regards
Rob.

sparkticus said:

Yes the fan is designed to have 12 Volts DC available (on load) at the 0 and +12 V terminals. What are you using to measure the voltage? I assume a multimeter set to DC VOLTS? If that is the case then it sounds like the stalled motor overloaded the power supply output. You will need to change it.

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I would not expect to find it running on DC. There may be some versions but a brushed motor does not really care if AC or DC so why include a rectifier?
Likely the transformer is damaged. I had the same problem with my fathers house and so in future it would not need bathroom floor lifting swapped to low voltage instead. Lucky at that point completion cert still had not been issued.
In hind sight should have used a heat exchanger and ceiling tiles but was in rather a hurry at the time.

I agree, unusual but that particular fan does indeed require DC. The PSU is a transformer and full wave bridge rectifier. The ICON fan is very compact and has all sorts of optional plug in electronic modules so it may be a space saving idea in addition to providing SELV. Having said that, they make a very similar 230VAC model.

Thanks fellas .
I will swop over the transformers today and let you know how I get on .
Regards
Rob.

Well its all up and running again .Looks like the transformer had given up also .
Thanks for the help fellas .
Regards
Rob .

Well done. If you have the space and opportunity it may be worth placing an inline fuse in the DC positive line just as it exits the power supply. This may well protect the power supply from overload in the future.

You will need to establish the normal running current. Use your multimeter on the DC amps setting and place multimeter in series with the load. I think you will find that its under 3 amps (around 2.4A) But you need to measure it because I am not certain.

Choose a fuse just above the normal running current.