HELP - New NVR switch does NOT stay on :(

[GDM]

Hi

I must say that these DIY NVR switches maybe cheap but I would not use in an industrial enviroment, a proper DOL starter is the way to go.

So Neutral to 13, Live to 23 when operated 14 is neutral and 24 live which you know is correct because it works whilst you hold the button in, so the hold in coil is not functioning. One end of this coil is internaly connected to 14 which is a neutral when the switch is operated, the other end A1 needs live to hold in and looking at your diagram this should work. With all the power OFF, and machine isolated check the hold in coil resistance between A1 and terminal 14, that should show a resistance and not be open circuit. It is looking like a faulty switch though.

Hello from Canada!

I'm having the same problem as TU described. I bought four no-voltage-release switches, and when I installed the first one, the load stayed on only if I pressed and held the green switch. I confirmed the wiring is correct. I swapped the switch with the other three switches, and of the four, only one switch worked (which tells me it's not a wiring problem).

I have a theory: Does the line voltage matter? In North America, line voltage is 125 AC. I ordered four 125v switches. But I received 250v switches. I'm now thinking that, for NVR switches, the stated voltage is not the maximum it can handle, but rather the voltage that it needs to operate. If my switches need 250v and are getting only 125v, could this be why they're not latching? If so, it might be a fluke that one of them actually works.

Thoughts? Many thanks in advance for your guidance.

 

[Spectric]

The voltage is your issue, with insufficient voltage then there will be insufficient current to create a magnetic field strong enough to hold the contacts in so you need to change the switchs for the correct rated items.

 

[ajs]

I have a theory: Does the line voltage matter? In North America, line voltage is 125 AC. I ordered four 125v switches. But I received 250v switches. I'm now thinking that, for NVR switches, the stated voltage is not the maximum it can handle, but rather the voltage that it needs to operate. If my switches need 250v and are getting only 125v, could this be why they're not latching? If so, it might be a fluke that one of them actually works.

Thoughts? Many thanks in advance for your guidance.

What Spectric said. If you read datasheets for relays they'll often give broad brush behaviour as supply voltage changes. Typical figures might be that it's specified to activate properly at maybe 75% of the rated voltage but only guaranteed to release at less than 20% of the rated voltage. Between those you generally have a wide (but undocumented and not guaranteed) region where the relay will hold its present value (on or off) and at the edges the precise thresholds depend on the quirks of the individual device, wear and tear, environmental conditions and so on.

That's for relays, although very similar from an electrical standpoint the expected use for an NVR is different. I'd expect the vast majority of relays to work at half the rated voltage in practice but would epect an NVR to cut out at a far higher voltage than that. After all, in a severe brownout at half the voltage and a quarter of the power I would expect the motor to stall in many cases which risks the same "leaping back to life" thing the NVR is there to stop. I wouldn't want to depend on fusing to cut power if the motor stalls since that same reduced voltage will also reduce the stall current.

 

[GDM]

What Spectric said. If you read datasheets for relays they'll often give broad brush behaviour as supply voltage changes. Typical figures might be that it's specified to activate properly at maybe 75% of the rated voltage but only guaranteed to release at less than 20% of the rated voltage. Between those you generally have a wide (but undocumented and not guaranteed) region where the relay will hold its present value (on or off) and at the edges the precise thresholds depend on the quirks of the individual device, wear and tear, environmental conditions and so on.

That's for relays, although very similar from an electrical standpoint the expected use for an NVR is different. I'd expect the vast majority of relays to work at half the rated voltage in practice but would epect an NVR to cut out at a far higher voltage than that. After all, in a severe brownout at half the voltage and a quarter of the power I would expect the motor to stall in many cases which risks the same "leaping back to life" thing the NVR is there to stop. I wouldn't want to depend on fusing to cut power if the motor stalls since that same reduced voltage will also reduce the stall current.

Thank you ajs and Spectric for your incredibly prompt replies. I have ordered four new switches (different supplier), and will confirm their voltage the moment they arrive. I truly appreciate your guidance. - Greg