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Timed Relay query

Keetybwoy

Apr 8, 2018
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Hi,
I would very much appreciate some help and advice please.
Our Tumble Dryer doesn't have a reverse function. Is there a relay with a timed function to switch polarity every few minutes I can install to the drive motor to enable this?

Thank you :)
 

Harald Kapp

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Is there a relay with a timed function to switch polarity every few minutes
The motor of your dryer is usually AC powered - polarity reverses 100 times (@50 Hz) or 120 times (@60 Hz) per second. Reversing polarity by a relay every few minutes will not change the direction of rotation.

Even if you could reverse the motor's rotation, the rest of the mechanics may not be built to operate reliably under such conditions.
 

ivak245

Jun 11, 2021
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Reversing in tumble dryers is done through 2 sets of windings- one CW, one CCW. The supply to the windings is switched electronically.
Easier to just buy a reversing tumble dryer.
 

Keetybwoy

Apr 8, 2018
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Thank you Harald and ivak245,

I thought it was a DC motor and not AC.

I appreciate your help and support :)
 

Bluejets

Oct 5, 2014
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Our Tumble Dryer doesn't have a reverse function.
Dryers with reverse are a totally different mechanical setup.
All you would achieve would be to jam the complete drive belt and tensioners.
If you want a reversing dryer, best is to buy one.
 

Keetybwoy

Apr 8, 2018
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This might sound a bit over the top, but what about swapping the AC motor for a DC one with an inverter? Is there a relay on the market which will do what I want?
 

Harald Kapp

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I don't know such a module, but maybe there is one or it can easily be built from a 555 timer IC and a relay.
This might sound a bit over the top
Scratch that a bit part.
You would need a DC power supply (not an inverter, that works in the other direction DC -> AC) able to supply enough power.
You will also have to integrate the control of the power supply into the existing control circuit of the dryer.
You will have to add a control logic that ensures that the tumbler has stopped before starting to turn in the reverse dirction. If you reverse the power to a running DC motor it will draw a very high current while slowing down and restarting.
And you will have to ensure that the mechanics are able to work bidirectionally (as mentioned twice above).
 

Bluejets

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This might sound a bit over the top, but what about swapping the AC motor for a DC one with an inverter? Is there a relay on the market which will do what I want?

Didn't read post #5 I take it.
 

Keetybwoy

Apr 8, 2018
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Thanks Harald and I get post #5 Bluejets, but I always believe there's a solution to everything, maybe not in this instance.

I appreciate all your help and knowledge, thanks.
 
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