Drill press will not start

[AStroudParticipant @astroud]

Hi

I have a Draper badged 16 speed drill press, 5/8″ capacity, with a 350W, 3A, 240V, 1400rpm motor.

Yesterday it would not start, the motor kicked for about 1 second and then stopped now it is dead, no humming or trying to start. With a circuit tester the 2 terminals in the connection box on the motor are live when the start button is pushed. All connections look tight and good.

I inspected the capacitor on the side of the motor, 75microFard, no sign of any damage. No sign of any centrifugal switch on the outside of the motor.

Any further checks I can do with my basic multimeter or just try and replace the capacitor?

[WaggonermanParticipant @waggonerman]

Check the Stop Button / contacts are not jammed in (it’s happened to me!).

waggonerman.

[noel shelleyParticipant @noelshelley55608]

The centrifugal Switch is inside the motor. You will need to dismantle to check this to be sure but if you can work out the wiring then you can at least see if you have continuity on the switch. Before dismantling make clear and unambiguous notes of wiring. Take the belt off, now what ?  That there is no sound and no attempt to start is bad. If the cap had gone it should still try to start, and if spun by hand may even run.  If it has the usual cheap switch/no volt release this as Waggonerman has said may have failed. Some multimeters do have a capacitor test function, though this may only be for small value Capacitors. Good Luck. Noel.

[Peter Cook 6Participant @petercook6]

If there is power reaching the motor terminals when the start button is pressed, then check the continuity of the windings. As Noel says if it was the capacitor (or centrifugal switch) you would expect the motor to hum and if spun may start up.

[AStroudParticipant @astroud]

Thanks for the advice.

Just done some further testing, good news is the motor runs when I wired it directly to a plug so looks like the start switch is faulty, odd though the motor terminals are live when I push and hold in the green start button on the drill.

I will replace the start switch and report back.

[Mark RandParticipant @markrand96270]

Possible that the coil of the NVR switch relay/solenoid* has gone open circuit. Also possible that the contacts or wiring  to the stop switch or any safety interlock switches have gone open circuit. Both of those cases should result in the motor starting when the start switch was held in though…

*pedant warning, i know that the coil is a solenoid, but people tend to think of the iron bits, not the copper ones.

[AStroud]

On AStroud Said:

odd though the motor terminals are live when I push and hold in the green start button on the drill.

Due to its high impedance, a DVM isn’t necessarily a reliable guide for testing a switch.

[Charles LamontParticipant @charleslamont71117]

If the stop switch or any interlock is open circuit then pressing the start should not do anything. Surely?

[Howard LewisParticipant @howardlewis46836]

If the NVR is double p[ole, failed contacts on the Neutral would prevent a start.

Has the solenoid winding in the NVR been checked? If that is open circuit, it will not latch in.

Replacement is the only solution.

Howard

[Chris CrewParticipant @chriscrew66644]

Given the brand of the drill I suspect we are talking about one of those cheap plastic NVR’s. They do work but if the small contacts they contain get hot or arc excessively, the contacts weld themselves to the yoke they are mounted in preventing contact being made. The device is easily dismantled by prising the side latches apart and it’s not rocket science to put things right if you use common sense and are not ham-fisted. I think I have described the repair in detail elsewhere so I am not going to repeat it here. Suffice to say if the contacts are beyond redemption a replacement device is available of eBay for just a few pounds.

[Clive FosterParticipant @clivefoster55965]

Further to what Chris says I feel it unwise to trust any “repaired” NVR unit if the work goes further than simply cleaning and, possibly re-setting contacts. Especially a modern made down to “a bit too low a price” device.

If a replacement is needed a proper stop-start box with industrial style contactor inside isn’t stupidly expensive compared to an import home shop rated device. Obviously folk like us don’t need the high end 24/7 industrial rated unit. An ordinary one will do fine. Frankly I’d be chary of like for like replacement of a failed NVR. Especially if it’s a mechanical issue. Failed won’t start is annoying but safe failed won’t stop is potentially lethal.

Even something as splendidly steam punk bolt together and massively over engineered as the two speed motor starter / control box onboard my wartime Pratt & Whitney B lathe isn’t something i’d want to seriously delve into.

Clive

[noel shelleyParticipant @noelshelley55608]

For what they cost just buy a new one ! Or go up market and fit a proper start switch which can have an overload device to save the motor, but it must have an overload to suit the motor eg 1/2Hp set to full load current. Now We’re up near £100 new. Good luck. Noel.

[AStroudParticipant @astroud]

Thanks.

I do have a cheap multimeter and have decided my check when pressing the start button is probably not valid. I have found a replacement start switch, it is on its way to me and I will report back.

Andrew

[EmgeeParticipant @emgee]

IP65 rated single phase starter in eBay £30, just state FLC from motor plate and 240v coil.

Emgee

https://www.ebay.co.uk/itm/156208633915?_skw=enclosed+motor+starter+240+coil&itmmeta=01JFW8V23HG7VF730WWAZ117RR&hash=item245ec2983b%3Ag%3AquoAAOSwCVxmOpLX&itmprp=enc%3AAQAJAAAA4HoV3kP08IDx%2BKZ9MfhVJKlgMJYZnymNtiDhBzZcWppNoSw0b83FeTKO7hKkNXLDp%2F9hvJTEVVr5uhpH4z9ldDbCI3TsiLOwu5DelIJF8ysLcrgqJ6UNSlcmf0VWfN1GGglMuV%2BXv%2F7eVOWSc%2Bc0YjZunseziGJDcvDiZeH%2B7SjmTP4xykX2LGs%2FSd2Lyu72Gd2dSfXFWnyzwfspruP0w9z23R4PxUoYeIjad0stoZYPOBlKrJFFkpaDP9%2B9vneba%2BaWRz9SqkVmLb0Fbh16QxAA8pBMidr9%2BK0LmpvFozWL%7Ctkp%3ABk9SR-6h7Ij_ZA&var=457119484934

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