Wiring Check

[jpor4180]

I've acquired a Clarke 2hp 6-10 amp 2 pole motor and the corresponding DOL starter for my Wadkin AGS 10" table saw

This would be the first motor I've wired and I found the wiring diagram on the starter especially difficult to comprehend. I see there are some posts about this before, but they are too old to see the pictures now and I would prefer to get this correct.

Here is how I think the motor wires up, taken from wiring diagram on capacitor housing:

Here is how I think the DOL starter wires up, taken from https://www.diynot.com/diy/threads/wiring-a-dol.225921/page-2 :

Left to right the housing reads 1/L1 3/L2 5/L3 on the top and 2/T1 4/T2 6/T3 on the bottom row.

I've used conventional colour coding for live and neutral, but just green for earth. My main question is does the earth look correct? There is no mention of it in the wiring diagram but nothing is double insulated so it needs it for sure.

Thanks in advance

 

[flh801978]

Your dol is correct but don't bother with the yellow wire just live and neutral in the top and follow through to the bottom using any pair of terminals. So L1 to T1. L2 to T2 for example

I cant see where your earth is going to on the motor but if there's no designated terminal just to the motor body

Ian

You do know that's there's no No Voltage Release ( NVR) on the dol starter?

 

[Sawdust Sam]

Your dol is correct but don't bother with the yellow wire just live and neutral in the top and follow through to the bottom using any pair of terminals. So L1 to T1. L2 to T2 for example

I cant see where your earth is going to on the motor but if there's no designated terminal just to the motor body

Ian

You do know that's there's no No Voltage Release ( NVR) on the dol starter?

The yellow wire is most likely required. It's a 3 phase DOL and it'll likely have phase loss protectionso, the yellow wire fools the phase loss protection. Might be worth trying just to prove but it'll definitely work with the yellow wire installed.

 

[jpor4180]

Your dol is correct but don't bother with the yellow wire just live and neutral in the top and follow through to the bottom using any pair of terminals. So L1 to T1. L2 to T2 for example

I cant see where your earth is going to on the motor but if there's no designated terminal just to the motor body

Ian

You do know that's there's no No Voltage Release ( NVR) on the dol starter?

Hi Ian,

Thanks for the help, from reading other posts on wiring a 3-phase DOL in single phase I agree with Sam on the yellow wire. I don't have any first hand experience on this matter though but I don't see the harm for a couple of pennies worth of wire

I feel so foolish now with the motor body. My first instinct would have been that but there is a reset switch with only the one wire going towards it so I assumed this would be some RCD to connect the earth to

There is, upon closer inspection, a really inconveniently placed screw 3 inches down into the housing, connected to the body, which can be seen under a magnifying glass to have the earth symbol next to it!

I had also assumed that the switch in the official wiring diagram in the original post referred to the DOL starter. Could it actually be the case that the live wire connects first to the reset switch and then to U2? Currently there is only one connection (from factory) at the reset switch

cheers,
Jacob

 

[flh801978]

Does the wire from the reset go to U2? If so connect your live to the other side of the switch which is probably a thermal overload switch.
I'm certain the dol doesn't need all connections required to be used its just a thermal overload on each wire...and as a byproduct it works for 3 phase too
Be aware you have no NVR protection which on a table saw is nice to have and essential if you are commercial or employing staff
Ian

 

[jpor4180]

Does the wire from the reset go to U2? If so connect your live to the other side of the switch which is probably a thermal overload switch.
I'm certain the dol doesn't need all connections required to be used its just a thermal overload on each wire...and as a byproduct it works for 3 phase too
Be aware you have no NVR protection which on a table saw is nice to have and essential if you are commercial or employing staff
Ian

Haha yeah the other side of the switch goes to U2, D'oh! Thanks, it's been a long day #-o

With regards to NVR, how does that function? Is that in case the thermal overload trips then when you press reset the saw won't automatically restart for example?

I am not commercial, just a weekend warrior at best, but I am looking maintain a professional standard of safety regardless so I will look into it further if you advise

Jacob

 

[flh801978]

The dol will trip out if there's an overload and not restart....but most importantly if there's a power outage the saw will stop but when the power is restored the saw will start up....there lies the danger
You need a contactor with start and stop buttons and a overload after that to protect the motor
All can be in a case no bigger than what you have and also a facility for wiring in a remote emergency stop button or multiples if you desire

Ian

 

[jpor4180]

Okay I see why that could be important if multiple people are using the saw. I think I can get away without that

I was going to just wire in a big red emergency stop button in series. So it's more accessible in an emergency than the DOL switch (which is also tiny)

However, because I don't have a DC brake, I doubt this facility would prevent an impending kick back

 

[Sawdust Sam]

The dol will trip out if there's an overload and not restart....but most importantly if there's a power outage the saw will stop but when the power is restored the saw will start up....there lies the danger
You need a contactor with start and stop buttons and a overload after that to protect the motor
All can be in a case no bigger than what you have and also a facility for wiring in a remote emergency stop button or multiples if you desire

Ian

No the saw won't restart on power restoration, DOL starters have a retaining circuit which will open deenergising the coil and therefore the contractor when power is lost. The only way thesawwill restart is if the start button is pressed, the retaining contact will then close again maintains power to the current il when the start button is released.

 

[flh801978]

I'm sure that that type will stay on on power outage
http://www.screwfix.com/p/hylec-direct- ... -5kw/8911g
This one however is what you want for use on a table saw

Ian

 

[Sawdust Sam]

I'm sure that that type will stay on on power outage
http://www.screwfix.com/p/hylec-direct- ... -5kw/8911g
This one however is what you want for use on a table saw

Ian

I'm sure you're wrong, are you a sparky or are you just guessing at this ?

 

[flh801978]

I specialise in industrial control electrics and electronics in the print industry

easy to check let Jacob wire in his starter get the motor running disconnect the power at the supply...leave the dol alone and let the motor stop then reconnect if it restarts it doesnt have a latch coil in it
Ian

 

[flh801978]

Actually even simpler without any wiring just the dol in your hand press the black start button in....does it stay in?

 

[jpor4180]

It stays in

 

[flh801978]

Thank you

 

[jpor4180]

So I wired it all up, took ages. There's a clunking sound, the motor spindle starts spinning and then comes to a stop

Could it be because I've soldered the earth wire to the screw of the housing as the screw was too tight to remove and I've got a bad connection?

If that is the case, is it safe to open up the motor housing if the capacitors are in there?

 

[jpor4180]

And then it started! I'm aware that start capacitors shouldn't be started more than 10 times an hour, so this started like 5th time. Should I be concerned or brand new motor stuff?

 

[flh801978]

Do you have a meter?
Wire straight in to the terminal block bypassing that "reset switch"
Your earth shouldn't give you that sort of error but you do need a good earth for safety
I wouldn't worry too much about starting it more than 10 times an hour i have had home machines starting big 3hp single phase motors at 10 times a minute with no long lasting probs
Your centrifugal switch (inside motor) could have been sticking to start with...is it all ok now?

Ian

 

[sunnybob]

I'm asking questions here, not giving advice, ok?

That dol, isnt that just a large resetable fuse contained inside a contactor?

I would think (open to correction) that a standard NVR switch would be all that was needed on that motor?

The thought that there isnt a NVR on a table saw is pretty scary, and I'm thousands of miles away!

 

[jpor4180]

Do you have a meter?
Wire straight in to the terminal block bypassing that "reset switch"
Your earth shouldn't give you that sort of error but you do need a good earth for safety


Your centrifugal switch (inside motor) could have been sticking to start with...is it all ok now?

I don't actually have a meter which is a pain, but I can source one. I can't attach this to the saw for the next two weeks or so as I'm getting a new pulley machined up.

I have a feeling it was just a sticky switch. I completely get your point about the earth and I am still slightly dubious about my handy work. I filed down the screw first to take off any finish, then I soldered the wire on. It was a very tricky solder because of lack of access and it took me a couple of attempts and refiling to get it right.

That dol, isnt that just a large resetable fuse contained inside a contactor?

I would think (open to correction) that a standard NVR switch would be all that was needed on that motor?

The thought that there isnt a NVR on a table saw is pretty scary, and I'm thousands of miles away!

My rudimentary understanding of a DOL is along the same lines as what you say, but that it has a different function to the ceramic fuse in the plug which can't discern between a start up current and an overload current.


Given that you are the second to voice concerns on the lack of NVR protection I think I'll need the danger explained to me. I'm sure I'm being naive

On a circular saw for example, I'll unplug it to change the blade and have the plug in my line of sight until I'm finished so I can't see any problems there. Ian mentioned yesterday that the real danger lies in loss of power to the workshop and then sudden reset. I'm going to install (or have someone install, not decided yet) a consumer unit to my garage (currently I run a single 13A power outlet and loads of extension leads, eek! I know) and so I guess I'll be in control of when it's reset. Provided I'm aware that if I don't switch off before reset it'll start up again, should there be anything to worry about?

Again, I'm not trying to shut off good advice, just to challenge my own understanding off the safety requirements.