AntonUK
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| posted on 1/1/15 at 10:25 PM |
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Lathe No Volt Switch
I have a cheapo NVR (No Volt switch) on my lathe.
After a period of about a month of no use (switched off at the wall during) it appears to have gone faulty.
Initially the relay buzzed, then when pressing 'ON' the lathe started, but would not turn off. If you hold the 'OFF' button it
will stop but only for the time the button is held.
I initially though the relay had failed so replaced it, but the new one is no different.
The switches appear to do what they are meant to according a continuity test, one being NC and the other NO.
Any ideas?
Build Photos Here
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theprisioner
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| posted on 1/1/15 at 11:47 PM |
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The principle is that of a Contactor. Basically if the power is interrupted then the machine will drop out if no one is there to reset it. It does
this with positive feedback from a third set of contacts (usually lower power) the third set hold in the contractor solenoid which keeps the machine
running. To stop the machine you open this contact or another in series with the holding current.
This may help:
http://www.claydons.org/public-html/elec/contactor.htm
http://sylvabuild.blogspot.com/
http://austin7special.blogspot.co.uk/
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