Discuss When connected to the fan voltage at connectors is 20v when disconnect from fan voltage is 220v. This down to the capacitor? in the Electrical Forum area at ElectriciansForums.net

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I'm struggling to make sense of that - could you re word it a bit.
 
It's most likely that you are measuring a ghost voltage an dthere is in fact no voltage there at all, what tester are you using?
 
It's most likely that you are measuring a ghost voltage an dthere is in fact no voltage there at all, what tester are you using?
I did think this however, i used my fluke mft and my normal martindale voltage tester, with proving unit. It was certainly live.
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I'm struggling to make sense of that - could you re word it a bit.
So i was called to a fan not working, it was an inline fan. I could easily access it so I just tested if there was voltage. In the exsiting connections i tested it and it read 20v AC. I thought it was strange thought the 20v might be off the capacitor (its an old fan) so i disconnected the feed and retested it, expecting 0v but actually had 220v AC. Ive recommended changing the fan in question but wonder if its something else
 
So i was called to a fan not working, it was an inline fan. I could easily access it so I just tested if there was voltage. In the exsiting connections i tested it and it read 20v AC. I thought it was strange thought the 20v might be off the capacitor (its an old fan) so i disconnected the feed and retested it, expecting 0v but actually had 220v AC. Ive recommended changing the fan in question but wonder if its something else

How would you get 20VAC from a capacitor?
Why did you recommend changing the fan? Nothing you've told us suggests that the fan is faulty as far as I can see.

A voltage which is present when there is no load but disappears as soon as a load is applied suggests that you have a problem with the supply, not the load.
I would suspect a loose connection somewhere in the supply circuit.
 
How would you get 20VAC from a capacitor?
Why did you recommend changing the fan? Nothing you've told us suggests that the fan is faulty as far as I can see.

A voltage which is present when there is no load but disappears as soon as a load is applied suggests that you have a problem with the supply, not the load.
I would suspect a loose connection somewhere in the supply circuit.
But us immediately rectified once disconnection from the device?
 
But us immediately rectified once disconnection from the device?

No it isn't rectified once the load is disconnected, you are just reading the open circuit voltage with the load disconnected.
With the fan connected you have a series circuit of the what I suspect is a high resistance connection and the load. So if the open circuit voltage is 220V and the closed circuit voltage across the fan is 20V then voltage across the high reisistance connection is 200V.
 
No it isn't rectified once the load is disconnected, you are just reading the open circuit voltage with the load disconnected.
With the fan connected you have a series circuit of the what I suspect is a high resistance connection and the load. So if the open circuit voltage is 220V and the closed circuit voltage across the fan is 20V then voltage across the high reisistance connection is 200V.
Nice one, il take the fan but check all connections as they are accessible. Thanks
 
as davesparkssays. a poor connection will give you volts on no load as there is no voltage drop. once load is connected and tries to draw current, the VD across the high resistance connection will reduce the voltage at the load. a low impedance meter liks a AVO 8 might show the low voltage on no load.
 
i would be tracing the live and N back through each of the joints and switches.
best guess is that it is the fan isolator switch.

measure the voltage across each switch pole i.e. live in to live out then N in to N out. whilst the fan is connected.
i expect you will find your missing 200v hiding in a switch somewhere!!
 

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