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I don't want this NVR switch

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Re: I don't want this NVR switch

Postby 9fingers » 26 May 2022, 21:50

The white wires will be a thermal switch that open when the motor gets hot. BUT the contacts cannot carry the motor current and are designed to operate the coil in the nvr ONLY.
So if you insist on not using the nvr not only are you discarding the safety aspects offered by the nvr you are also rejecting the over temperature cut off.

Bob
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Re: I don't want this NVR switch

Postby sunnybob » 27 May 2022, 04:33

Doesnt removal of a safety device leave oneself wide open to blame for any accident involving that machine in the future?
I wonder why you would want to?
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Re: I don't want this NVR switch

Postby wthrelfall » 31 May 2022, 11:22

Bob, many thanks for your reply. I do intend to use an NVR, but I would like to put it in circuit before a remotely switched relay which I already own (https://toughleads.co.uk/collections/wo ... 3a-and-16a). Is this a possibility?

9fingers wrote:The white wires will be a thermal switch that open when the motor gets hot. BUT the contacts cannot carry the motor current and are designed to operate the coil in the nvr ONLY.
So if you insist on not using the nvr not only are you discarding the safety aspects offered by the nvr you are also rejecting the over temperature cut off.

Bob
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Re: I don't want this NVR switch

Postby 9fingers » 31 May 2022, 12:14

Yes it should be do-able.
Use the white temp sense wires in the normal way with your nvr* and insert your relay in the main motor leads between the nvr ouput and the motor power input.

*follow the existing wiring scheme as regards the white wiring as different motors do it slightly differently.

You might have to only switch one of the power wires with your relay to stop the nvr dropping out when your open the relay.

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Re: I don't want this NVR switch

Postby sunnybob » 31 May 2022, 13:18

I made modifications to my dust collector, to enable remote switching from each end of the bank of machines.
maybe this will help.;
Cut into the live wire from the NVR (the one that becomes live when the NVR is pressed), and route that wire to any other switch you want to add, then take the live back to the nvr box and connect it to the receiving wire.

That way I still have to use the mains wall switch AND the nvr first thing in the morning, but from then on I can start or stop the blower from wherever I am working. When I shut down at night I turn the wall switch off. If there is any unexpected interruption during the day, the NVR still works as planned.
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Re: I don't want this NVR switch

Postby 9fingers » 31 May 2022, 14:09

That may well have worked in your case Bob but motors with these thermal sensors have several ways of connecting the sensor. Some are common to one end of the run winding so that motor connection needs to be permanently connected through to the NVR.
In this case as there seem to be two sensor wires, then the sensor could well be isolated from the windings who knows.
My concern is that the OP might not know either or be aware of the significance hence my advice to keep everything wired as is and then introduce the NVR.

Options are made all the more difficult as I think the NVR in use is not a full DOL motor switch system but one of the rather technically unpleasant KEDU switches with an electro mechanical NVR where the stop button forces apart the magnetic poles rather than operation on the coil electrically.

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Re: I don't want this NVR switch

Postby sunnybob » 31 May 2022, 14:23

My simple world answer (suits you sir) :oops: , is to merely interrupt the live immediately at the NVR exit, therefore not impinging on any other wire or switch.

Worked for me, 4 years now without a problem, used many times a day, but I'm not guaranteeing it will work for everybody. :eusa-whistle:
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Re: I don't want this NVR switch

Postby 9fingers » 31 May 2022, 14:27

sunnybob wrote:My simple world answer (suits you sir) :oops: , is to merely interrupt the live immediately at the NVR exit, therefore not impinging on any other wire or switch.

Worked for me, 4 years now without a problem, used many times a day, but I'm not guaranteeing it will work for everybody. :eusa-whistle:


Yes Great for you Bob in your application but in some instances interrupting the "wrong" wire will/can cause the NVR to drop out.
Giving advice here has to bearing mind different implementations as well as not all reader have the knowledge to dig themselves out of the hole they have just dug.

Bob
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Re: I don't want this NVR switch

Postby spb » 31 May 2022, 18:11

For example, the Record PT260 wiring diagram:

Image

The live wire from the output of the NVR to the motor also connects to the overload switch in the motor housing, then back to the cut-out microswitches that check the tables and guards are in the right places. Interrupt the supply to the motor, and it'll have the same effect as triggering the thermal cutout, turning off the NVR.
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Re: I don't want this NVR switch

Postby 9fingers » 31 May 2022, 18:57

Excellent example :text-goodpost:

The only place to put a relay in that circuit to avoid tripping the NVR would be in the grey wire going to the motor.

Bob
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Re: I don't want this NVR switch

Postby wthrelfall » 31 May 2022, 19:33

Bob, this worked perfectly. Grateful for your explanation!



9fingers wrote:Yes it should be do-able.
Use the white temp sense wires in the normal way with your nvr* and insert your relay in the main motor leads between the nvr ouput and the motor power input.

*follow the existing wiring scheme as regards the white wiring as different motors do it slightly differently.

You might have to only switch one of the power wires with your relay to stop the nvr dropping out when your open the relay.

Bob
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Re: I don't want this NVR switch

Postby 9fingers » 31 May 2022, 21:16

Very happy to help!

It's what we do here.

Bob
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