Another NVR switch failure

[Mike G]

The NVR switch on my new bandsaw is failing. Are all replacements the same, or are some better than others?

 

[AJB Temple]

If you want industrial quality look at the Farnell UK web site.

For less cost, I have used these 16 amp switches with emergency stop. Not had any problems. You can also find paddle stop and also foot switches if you hunt around. The industrial gear such as sold by Farnell is much more robust, but so are the prices.

Watch for the amperage rating.

 

[Lurker]

Assume that you have checked that it's not full of sawdust?

Also, I have had two incidences with different machines where the flexible plastic cover interferes with the off button . Removed the cover and all is well.

 

[Mike G]

Assume that you have checked that it's not full of sawdust?

Erm.....no......That's a thing, is it?

 

[Mike G]

For less cost, I have used these 16 amp switches with emergency stop. Not had any problems.......

I'm not sure if you meant to include a link, Adrian.

 

[Lurker]

Assume that you have checked that it's not full of sawdust?

Erm.....no......That's a thing, is it?

From various fora posts about NVRs it's the most likely thing. Never happened to me though.

 

[9fingers]

If you are using KEDU type switches then these are very poor, unreliable and offer no overload protection to the motor (although sometimes the motor has a thermal switch internally which helps)

A proper DOL style switch with integrated current overload switch correctly selected to match the motor rating are far superior.

KEDU is a make, DOL is Direct On Line

Bob

 

[Mike G]

My assumption, Bob, is that it is the original switch. It's Kedu.









I've blown it out with an airline, and it's working, but that tells me nothing. It works most of the time, until it doesn't, when it won't lock into the ON position..

 

[Lurker]

Take off the clear plastic switch cover and see what happens.

 

[Mike G]

I did, and gave it a good clean. There seemed to be no dust anywhere, but I blew everything through with an airline. As I said, the problem is that it works most of the time, so I can't tell if I have fixed it or not.

 

[Lurker]

You misunderstand.
I have had two machines where the clear protective cover fouled the off switch.
Remove it completely, run the machine without it for a day or two, easy to replace if it is not that.
I know it sounds a bit daft.

 

[AJB Temple]

This site tech drives me crazy. I posted details of a DO switch we installed and a much cheaper (less good) Kedu with links to both and the post never appeared because someone else posted in the meantime, even though I pressed submit and then resent. It happens so often and puts me off posting here at times as the site is so slow to update and does not save work. Antiquated is not the word. Unfortunately I shut down that laptop in the meantime and so can't backtrack to what I wrote.

Edit. And it's just done it again with this post FFS!

 

[Mike G]

You misunderstand.
I have had two machines where the clear protective cover fouled the off switch.
Remove it completely, run the machine without it for a day or two, easy to replace if it is not that.
I know it sounds a bit daft.

Oh, I see. Well, I can give that a whirl.

 

[Lurker]

This site tech drives me crazy. I posted details of a DO switch we installed and a much cheaper (less good) Kedu with links to both and the post never appeared because someone else posted in the meantime, even though I pressed submit and then resent. It happens so often and puts me off posting here at times as the site is so slow to update and does not save work. Antiquated is not the word. Unfortunately I shut down that laptop in the meantime and so can't backtrack to what I wrote.

Edit. And it's just done it again with this post FFS!

Tempting fate, but I have never had problems.
Also my old I pad (We have two) refuses to talk to another forum that uses up to date tech.

 

[9fingers]

Mike, OEM or not, KEDU switches are a regular source of problems for folk to who come to me with motor issues.

Over the years they have introduced the cover that Lurker mentions to give an element of sealing against moisture and the biggest enemy, dust but this can introduce the problem to which Lurker refers.

Bob

 

[Mike G]

Assuming this severe clean doesn't work, what alternative would you suggest I look at buying, Bob? I don't want to be running into these problems again.

 

[9fingers]

Assuming this severe clean doesn't work, what alternative would you suggest I look at buying, Bob? I don't want to be running into these problems again.

I normally buy a DOL starter from toolstation but they seem to have dropped them from the range. Screwfix only seem to offer 3 phase ones.
Electrical wholesalers seem to be very expensive unless you have an account with one after all your house building electrics purchases? or do you have a tame sparky with an account to get you trade prices.

You need a switch with a 240v coil and separately an overload relay with its current range nominally centred on the current rating from your motor plate to fit inside the switch box.

WIring is not difficult but ways to do it depend on what you already have there and if the motor itself has a thermal switch in it. I'd be tempted to ask DaveL for assistance just don't tell him I suggested it

Bob

 

[Mike G]

Thanks Bob.

 

[AJB Temple]

This is about the cheapest DOL switch you are likely to find Mike:

https://www.ebay.co.uk/itm/202692877959 ... ntid=87779

Comes in single phase, 16amp version.

I have a trade account with both CEF and TLC which you are welcome to use, but both of them tend to supply RS or Schneider gear for this application and the price will be much more, even after discount. CEF are notoriously expensive unless you spend a lot with them. TLC much better.

 

[DaveL]

Assuming this severe clean doesn't work, what alternative would you suggest I look at buying, Bob? I don't want to be running into these problems again.

I normally buy a DOL starter from toolstation but they seem to have dropped them from the range. Screwfix only seem to offer 3 phase ones.
Electrical wholesalers seem to be very expensive unless you have an account with one after all your house building electrics purchases? or do you have a tame sparky with an account to get you trade prices.

You need a switch with a 240v coil and separately an overload relay with its current range nominally centred on the current rating from your motor plate to fit inside the switch box.

WIring is not difficult but ways to do it depend on what you already have there and if the motor itself has a thermal switch in it. I'd be tempted to ask DaveL for assistance just don't tell him I suggested it

Bob

I heard that [emoji38]


Mike,

Do you want me to sort this out, like I did for the old saw?

 

[Mike G]

Not just yet, Dave, thanks. Let's see if blasting it out with an air line has done the trick. I'll try it without the dust cover for a while, too.

 

[9fingers]

This is about the cheapest DOL switch you are likely to find Mike:

https://www.ebay.co.uk/itm/202692877959 ... ntid=87779

Comes in single phase, 16amp version.

I have a trade account with both CEF and TLC which you are welcome to use, but both of them tend to supply RS or Schneider gear for this application and the price will be much more, even after discount. CEF are notoriously expensive unless you spend a lot with them. TLC much better.

:text-goodpost: agree 100% . Good spot with that ebay item. I'm sure I've used that vendor before successfully.
Bob

 

[Mike G]

This is about the cheapest DOL switch you are likely to find Mike:

https://www.ebay.co.uk/itm/202692877959 ... ntid=87779

Comes in single phase, 16amp version.

I have a trade account with both CEF and TLC which you are welcome to use, but both of them tend to supply RS or Schneider gear for this application and the price will be much more, even after discount. CEF are notoriously expensive unless you spend a lot with them. TLC much better.

Thanks Adrian, that's brilliant.

 

[Lurker]

There is one available for collection at my local tool station, when it’s gone it’s gone on it.
Might be worth checking your local branch.

 

[Phil Pascoe]

https://www.toolstation.com/axiom-dol-s ... %20starter

 

[Mike G]

Thanks Phil. Out of stock at my local branch and for delivery, apparently. Ho hum.

 

[DaveL]

Thanks Phil. Out of stock at my local branch and for delivery, apparently. Ho hum.

I had already checked that, I bought one that's on my table saw, they are good, it's a pain they have dropped them.

 

[spb]

One available in Cambridge, depending how much you want it...

 

[Phil Pascoe]

I've paid for the 240v 4kw one if you want it, Mike. It won't cost much to post. :lol:
I can leave it there if not.

 

[Mike G]

Hang on a sec. What's happening?

 

[9fingers]

Guys, Don't forget that the overload relays are not included but have to be bought as well AND they need to be from the same maker as the NVR to ensure they fit mechanically as well as electrically. The relay need to be selected to match the motor.
As these toolstation NVRs are going extinct, finding an overload could be a problem.

Bob

 

[AJB Temple]

^^^ See Bob's post.

The one I linked to has overload relay built in and the seller is helpful and will assist in making sure it matches your motor. When I bought one (with guidance from an electrical engineering bloke) it was for a single phase large motor running a cyclone and the seller provided a plug and play solution to fit the motor spec. Unlike Bob I have little knowledge of motors but this did work fine and my electrician at the time was happy.

My limited understanding is the overload relay protects the motor windings from overcurrent and prevents fires, but allows the high start current to get the motor moving. Trouble is if you buy separately, from what we discovered at the time, it racks the cost up and you need to know what type of relay is required for your set up (I think from memory they are solid state, thermal or magnetic).

Disclaimer: Bob is an expert/ I am not :lol: