Dol starter or just a plug is it really worth it?

[Grant Allen 1Participant @grantallen1]

I'm looking at wiring up my mtype lathe, the original switch hummed like caged angry bees so I've decided to bring it into the future. But I'm trying to work out whether to stick a plug on the end and use a kedu switch or put a dol switch on. Is it really worth the extra ?

[Grant Allen 1Participant @grantallen1]

[clogsParticipant @clogs]

U don’t say if it's 3phase….all my 3phase machine have dol starters….

i have several pillar drills that I have binned the starter buttons and now use an outside type light switch…

not strictly the best idea but it works for me…..it's only me that uses them….

never a prob in 10 years….they are only fractional motors….

[EmgeeParticipant @emgee]

Grant, whichever method you use it is best to consider an easily accessable Emergency stop type button to switch the spindle motor off in case of an emergency when you are using the lathe, it could safe you serious injury or even worse,

Emgee

[john fletcher 1Participant @johnfletcher1]

Well it come down to how much you value your fingers and life. DOL starter with NO-VOLT release every time and considering the protection they give, they are not so expensive. You might be lucky and pick one second hand. With a bit of luck and care a 415 volt one can be altered to work on 240 volts. If you take some photos and make notes you can carefully dismantle a starter,Take out the operating coil measure its resistance R1 and remove turns of fine copper wire, about 40% need to come off. 240/415 X 415 is the final ratio = R2. then put it all back. together again. John

[Ian McVickersParticipant @ianmcvickers56553]

Starter unit with overload protection would be my recommendation. You will have start function, stop function and prevention against auto restart in case of power fail. You can also extend the stop circuit by adding additional estop if required.

[Ian PParticipant @ianp]

I've no idea what a kedu switch is but DOL are mainly used for three phase motors wired directly to three phase motors. If yours is a single phase then a NVR is ideal if its just on/off, with a reversing switch (if fitted) between it and the motor.

If its at three phase motor running of a VFD then apart from an emergency stop (easily wired into the VFD control) you need an isolating devic e which could be just a 13A plug switched off, or pulled from the wall socket or it could be a more industrial wall mounted isolator which is just feeding that machine. VFDs usually have the NVR facility enabled by default.

Ian P

[Peter G. ShawParticipant @peterg-shaw75338]

John, you beat me to it! But I would just query one thing with you. The DOL switch on my lathe was re-arranged for both single phase and three phase simply by re-arranging the internal wiring. The contactor coil was connected across one of the three phases and neutral, this being equivalent to a single phase circuit. No need to mess around removing turns of wire.

Otherwise, they can indeed be easily dismantled & reassembled. In my case, the coil failed, so I replaced the coil with a plug-in mains relay and rebuilt the insides to give the same facilities.

An edit: Yes it is worth it for the NVR function alone.

Peter G. Shaw

 

Edited By Peter G. Shaw on 25/04/2019 21:09:22

[Mike PooleParticipant @mikepoole82104]

Any machine where you are going to be intimately involved with the rotating parts such as a lathe, pillar drill or mill etc. are capable of seriously hurting you if they are started unexpectedly. A motor starter will provide you with protection from an unexpected restart after a power interruption (NVR), overload protection for the motor if you fit the overload module and the possibility of remote start and stop buttons and additional emergency stops in useful places. Safety should not rely on you remembering to do something. If you experience a power cut in the workshop while a machine is in auto feed would your first thought be to turn the machine off or find your way out in the dark to find a torch or candle? If your lathe was under auto feed then when power is restored it will carry on cutting until something breaks or the motor burns out, a starter might seem like a bargain then.

Mike

Edited By Mike Poole on 25/04/2019 21:34:55

Edited By Mike Poole on 25/04/2019 21:36:23

[Grant Allen 1Participant @grantallen1]

Thanks all for your advice, should I go for a dol starter or a kedu nvr machine switch.?

I have a separate emergency stop button which I will place somewhere on the bench.

[Sam Longley 1Participant @samlongley1]

Posted by Emgee on 25/04/2019 20:28:48:

Grant, whichever method you use it is best to consider an easily accessable Emergency stop type button to switch the spindle motor off in case of an emergency when you are using the lathe, it could safe you serious injury or even worse,

Emgee

What? worse? you mean as in damage a couple of days work??

Edited By Sam Longley 1 on 26/04/2019 08:06:23

[Mike PooleParticipant @mikepoole82104]

The kedu switches do not have overload protection and some at least do not have the facility for extra estops or remote start buttons. Tool station do a DOL starter and overloads to suit and that is what I would use. Additional estops should be wired in the coil circuit and not carry motor current as they are not designed for switching power loads but just control circuit signals.

Mike

[Grant Allen 1Participant @grantallen1]

Cheers Mike. I will get a dol startr and overload but may need a wiring diagram to add the e.stop.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Grant, various types available from Axminster Tools **LINK**.

Regards Nick.

[EmgeeParticipant @emgee]

Posted by Sam Longley 1 on 26/04/2019 08:05:46:

Posted by Emgee on 25/04/2019 20:28:48:

Grant, whichever method you use it is best to consider an easily accessable Emergency stop type button to switch the spindle motor off in case of an emergency when you are using the lathe, it could safe you serious injury or even worse,

Emgee

What? worse? you mean as in damage a couple of days work??

Edited By Sam Longley 1 on 26/04/2019 08:06:23

Sam, worse would be "critical" (just noticed my error, should be save not safe)

Emgee

[Grant Allen 1Participant @grantallen1]

Would this be a practical solution or should it be a dol starter

https://www.axminster.co.uk/axminster-nvr-switch-c-w-box-230v-1ph-340181

[Grant Allen 1Participant @grantallen1]

The motor I'm using has a full load of 2.53 amps, so do I stick to a range ie 2-5 amps overload or would say upto 7 amps be suitable if I decide to change the motor.?

[Ian McVickersParticipant @ianmcvickers56553]

2 to 5 amps would be a good range to cover the motor you are using. Overloads are not expensive and would be easy to change if you decide to fit a bigger motor in the future.

[Grant Allen 1Participant @grantallen1]

Hi Ian theres one going on Ebay that 3-5 amps would this be suitable or is it too high. It's a brook crompton one ?

[EmgeeParticipant @emgee]

As others have suggested a DOL starter will in addition to NVR will also provide motor protection if you fit an overload unit.
You can also fit remote EMstop/start station's in the DOL starter control circuit.

Pic shows a combined DOL starter with overload unit and switch fuse for isolation.

Emgee

Edited By Emgee on 26/04/2019 10:27:14

[Ian McVickersParticipant @ianmcvickers56553]

Personally I think it's too high. I wouldn't use it for that motor if it's was me doing the job. If buying one from eBay make sure it comes complete.

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Grant, I have to agree that overload protection plus NVR is the best thing to use. If your motor goes into overload mode, you may be to late to hit the E-stop before permanent damage is done to the windings of your motor.

Regards Nick.

[Grant Allen 1Participant @grantallen1]

Thanks for that Ian for that advise. I'll look for a dol with a 2-5 amp overload. Would a nvr be an extra or does the dol starter act as one ?

[Ian McVickersParticipant @ianmcvickers56553]

The no volt release is built into the starter. When the start button is pressed the contactor pulls in , provided the stop button contact and overload contact is closed. The start button is wired in parallel across a contact on the contactor and this holds the contactor in after the start button is released. If the power fails the hold on contact is released and the contactor drops out. This is the NVR circuit.

Edited By Ian McVickers on 26/04/2019 10:52:53

Edited By Ian McVickers on 26/04/2019 10:53:41

[Nicholas FarrParticipant @nicholasfarr14254]

Hi Grant, DOL's should have NVR built in, but they may not contain overload protection, although most will allow overload of the required rating to be added into the same box.

Regards Nick.

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