Are all NVR switches the same?

[Mike G]

Yeah, I know they're not. But single phase plastic things that looks the same externally?

I have a dodgy NVR switch on my bandsaw, which needs replacing. I have a perfectly good one on my extraction system motor, which I intend bypassing to switch via a double pole isolating pull switch (switching the socket). Is there any reason I can't just swap the extractor one onto my bandsaw?

 

[Dr.Al]

The only likely difference might be current rating, but I'd expect that two that look the same externally would be likely to have a similar rating.

In my (limited) experience, when NVR switches start being "dodgy", it's usually corroded contacts as a result of arcing due to being connected to an inductive load (i.e. a motor). If that's the case, then it usually isn't that hard to get them apart enough to clean the contacts with a file & give them a new lease of life. Of course you might decide life's too short.

 

[Doug]

Check the amp rating is the same Mike also if either has thermal overload protection

 

[Spectric]

They fall into two basic categories, the compact plastic ones found in most DIY machinery and then the industrial Direct Online Starter (DOL) used in industry and with a built in adjustable overload.

which I intend bypassing to switch via a double pole isolating pull switch (switching the socket).

Make sure the pull switch is not a 6 amp one for lighting, you need something higher rated for a socket.

Check the wiring on the extraction system motor NVR and see if it is going to be an easy swap, there are variations in connections.

 

[Cabinetman]

Can also be dust inside the thing.

 

[Eric the Viking]

Can also be dust inside the thing.

Wot eee said.

In my limited experience bandsaw dust gets jolly everywhere, including into the switch.

Mine still works, but will get a blast with the vacuum cleaner at the first sign of misbehaviour...

 

[Distinterior]

The NVR switch on my 2.2kw bandsaw stopped working correctly a couple of years ago, so I ordered a replacement.
When it arrived, I removed the original switch from the bandsaw and noticed there was a small amount of dust visible inside the transparent cover over the coil.....I thought Ive got nothing to lose, so took the cover off, blew it out and cleaned as much as I could, reassembled the original switch and re fitted it and Bingo!...It was working properly again! It's worked fine ever since

I ended up fitting the new replacement switch on my Startrite pillar drill, as the original switch did not have NVR protection.

 

[Mike G]

I've blown my switch through 5 or 6 times with an air line, and that's fixed it every time until this time. That's why I thought I needed a new one. However, I did some additional dismantling this time, following Al's suggestion, and cleaned the terminals. It's now working again.