Fixing the electrics in my old German mill Ruhla 250/710
- Bill Shields
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Re: Fixing the electrics in my old German mill Ruhla 250/710
Well that is good.
Too many things going on to bother listing them.
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Re: Fixing the electrics in my old German mill Ruhla 250/710
Your relays will be fine. A transient protector in parallel with each coil could lengthen contact life.
- tornitore45
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Re: Fixing the electrics in my old German mill Ruhla 250/710
...lengthen contact life of the driving relay.Your relays will be fine. A transient protector in parallel with each coil could lengthen contact life.
AC snubber you can start with R=1/2 x Rcoil and C = 0.47uF or less X Rated Capacitors are NOT rated as Movies
Values have wide latitude when one has not much data on coil
Mauro Gaetano
in Austin TX
in Austin TX
- liveaboard
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Re: Fixing the electrics in my old German mill Ruhla 250/710
All I understand from that is capacitors.tornitore45 wrote: ↑Thu May 27, 2021 12:31 pm
AC snubber you can start with R=1/2 x Rcoil and C = 0.47uF or less X Rated Capacitors are NOT rated as Movies
I intend to add reversed diodes to the clutch + brake coils to drain reverse emf when disconnecting.
We know that when this machine was built, silicone diodes weren't available...
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Re: Fixing the electrics in my old German mill Ruhla 250/710
Measure the resistance of one of the relay coils. That's Rcoil. Connect a resistor equal to Rcoil/2 in series with a .47 uF capacitor. Connect that series combination in parallel with the relay coil. Do that for each relay. Use 1/4 watt resistors and 100 volt or higher ceramic capacitors.
Or connect a 50 volt transient protector (MOV or TVS) across each coil.
Or connect a 50 volt transient protector (MOV or TVS) across each coil.
- liveaboard
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Re: Fixing the electrics in my old German mill Ruhla 250/710
got it, thanks for the clarification.
But with 230v coil voltage, don't I need capacitors rated at 230+ ?
But with 230v coil voltage, don't I need capacitors rated at 230+ ?
- Bill Shields
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Re: Fixing the electrics in my old German mill Ruhla 250/710
Unless you like fireworks...yes on higher voltage
Too many things going on to bother listing them.
- liveaboard
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Re: Fixing the electrics in my old German mill Ruhla 250/710
I love fireworks.
Maybe not in the workshop though.
Maybe not in the workshop though.
- tornitore45
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Re: Fixing the electrics in my old German mill Ruhla 250/710
The diode is good for any coil that is DC driven.
For coils AC driven a MOV rated Higher than the line voltage or a RC snubber as John described. R + C in series rated for line voltage.
TVS are like 2 Zener diodes back to back they are a Semiconductor "equivalent" of the MOV
For coils AC driven a MOV rated Higher than the line voltage or a RC snubber as John described. R + C in series rated for line voltage.
TVS are like 2 Zener diodes back to back they are a Semiconductor "equivalent" of the MOV
Mauro Gaetano
in Austin TX
in Austin TX
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Re: Fixing the electrics in my old German mill Ruhla 250/710
I somehow got the impression that you had a 24 V control transformer. Yes, the snubber network components must be rated for the coil voltage plus a comfortable margin.liveaboard wrote: ↑Fri May 28, 2021 2:10 am got it, thanks for the clarification.
But with 230v coil voltage, don't I need capacitors rated at 230+ ?
- liveaboard
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Re: Fixing the electrics in my old German mill Ruhla 250/710
230v control transformer; input voltage is 380.
Some other models by this company did use 24V control.
Some other models by this company did use 24V control.
- liveaboard
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Re: Fixing the electrics in my old German mill Ruhla 250/710
I'll connect the power tomorrow.
I'm only slightly terrified.
I'm only slightly terrified.