Hoover motor died I think

This topic has 23 replies, 8 voices, and was last updated 20 November 2016 at 10:19 by Les Jones 1.

Viewing 24 posts - 1 through 24 (of 24 total)

Author

Posts
15 November 2016 at 07:45 #266662
sean logie
Participant
@seanlogie69385
Started the lathe up last night and the motor didn’t sound happy at all ,the light in my shed were flickering the motor sounded like an engine running rough then I noticed smoke coming out of the end of it where the cables enter ,also noticed the piggy back capacitor was warm . Think there’s a good chance the motor has had it . What do you guys think .

Sean
Advert

15 November 2016 at 07:45 #32828
sean logie
Participant
@seanlogie69385
15 November 2016 at 08:20 #266667
Les Jones 1
Participant
@lesjones1
You either need to investigate the cause of the problem. Dismantle the motor and look fo obvious faults like faulty insulation on the wiring. (I think being a hoover motor it may be so old the wires have rubber insulation.) Check the oppertion of the centrifuglal switch and the state of the contacts. Check the insulation between the windings and earth and between each other. Check the capacitor. Check that the bearings are not so bad that rotor is in contact with the stator. The alternative is to get a new motor.

Les.
15 November 2016 at 08:29 #266670
Brian Oldford
Participant
@brianoldford70365
If you have been as lucky as I was you might get away with it. Some months ago the the Brooks Crompton motor on my lathe started to emit the magic smoke of death. Fortunately I switched off within a second or two of seeing the smoke. Removal and dismantlement at my local motor rewinders revealed a centrifugal switch with welded contacts. Replacement followed by a thorough check of the insulation revealed it to have returned to fit to work at very modest cost. I hope you dodge a bullet as I did.
15 November 2016 at 09:03 #266674
mark smith 20
Participant
@marksmith20
My south bend came with an hoover motor with one large capacitor on the side. I was going to initially use it but on testing the capacitor blew up ,this was in the house and the smoke was everywhere. Does this mean the motor is scrap or just the capacitor??

I still have the motor but used a 3ph and inverter on the lathe.
15 November 2016 at 09:55 #266684
sean logie
Participant
@seanlogie69385
The cable are wrapped on a kind of clothe material ,checked the bearings, the bearing on the pulley end is not perfect but I can’t feel any play . The motor acted like it was stuttering before I switched it off . Will have a proper investigation tonight . Thanks for all the input ,don’t mind admitting that electrics scare me …. .

Sean
15 November 2016 at 15:52 #266728
mark smith 20
Participant
@marksmith20
Sean .is your motor like this in the photo of my south bend when i bought it.

Edited By mark smith 20 on 15/11/2016 15:53:26
15 November 2016 at 17:01 #266735
An Other
Participant
@another21905
Mark – your motor is probably not dead – I have had many capacitors fail in various motors, usually fairly obviously. They may develop a bulge on the side, or the end pushes out slightly. The capacitors are usually marked with their value, and depend on the motor. Look for a marked value in microfarads (uF) – probably between 10 to 35 uF.

Just buy a replacement capacitor and fit it. You must get the correct type for use with a motor, with the correct working voltage – usually around 400 V.A:C. They are not polarized, which means the connections can be either way (no '+' or '-&#39. You might have to do a bit of searching to find out where to buy one – I am lucky – where I live is a shop which seems to sell all the things you can never normally find.

I guess in the UK places like Maplin might stock them.
15 November 2016 at 18:09 #266739
john fletcher 1
Participant
@johnfletcher1
If the capacitor is getting warm after such a short time I think you have the answer. For a quick test, slacken off the drive belt, making sure you can revolve the motor pulley by hand. With the power OFF, cut the capacitor wires join them together with a choc block connector. In other words you have isolated the start capacitor. Switch on the motor it should start on No load, not as normal though. Be ready to switch OFF if things are not well. If it does start then you have solved your problem and tested the winding as well. The capacitor gives the motor the starting torque it needs and without it, it will hardly pull a chicken off its nest, as granddad would say. Maplin, RS, Farnel and your local rewind shop will sell a replacement. Reading Les Jones 1 comments above, check that the rotor is not rubbing, as I seem to remember that some Hoover motors used bushes both ends and if you have had the belt really tight you might have worn out the drive end bush. John
15 November 2016 at 19:02 #266744
sean logie
Participant
@seanlogie69385
No Mark ,my motor is tucked away in the pedistle that the lathe sits on .

Sean
15 November 2016 at 19:30 #266748
sean logie
Participant
@seanlogie69385
Hi John , do you mean disconnect the capacitor completely from the motor . If this is the problem could this have caused the smoking ?

Sean
15 November 2016 at 19:37 #266749
sean logie
Participant
@seanlogie69385
I’ve added a photo of the capacitor in my albums.

Sean
19 November 2016 at 09:24 #267257
john fletcher 1
Participant
@johnfletcher1
Hello Sean, Ignore my previous posting, whilst it is valid its not applicable to your motor at this time. Having a bit more sleep and thinking about the motor some more, as start capacitors are short time rated and if the motor centrifugal switch had remained closed for what ever reason, welded contacts for example, then the capacitor would be in circuit all the time, not short time. No wonder the capacitor got warm.The motor start circuit consists of the capacitor, the centrifugal switch and the start winding form a series circuit all short time rated. So, having second thoughts I think your motor has centrifugal switch problem. Its not a big job once you have got the motor on the bench to strip it down and locate the switch, it will be attached to the NON drive end cover. The operating part of the switch is attached to the rotor, bob weights fly out and push the contact apart, when the motor is up to speed. Make sure the mechanism are free to operate, don't oil it, usually there are two return springs. Hopefully you have saved your motor, the capacitor may also be Ok, they are not expensive. I hope the above is some help. John
19 November 2016 at 11:20 #267277
mark smith 20
Participant
@marksmith20
I Have a similar motor (though 1/2HP) i was hoping to fit to a south bend im doing up to sell , the capacitor blew up and unfortunately i must have threw out the capacitor as apart from all the smoke it was leaking some smelly liquid??

Heres the motor plate compared to Seans, any idea what size capacitor might get it working again? The capacitor that blew was a large plain aluminium can type .

Might i also have a problem with the centrifugal switch ?

Thanks

Edited By mark smith 20 on 19/11/2016 11:25:29
19 November 2016 at 11:27 #267280
sean logie
Participant
@seanlogie69385
Think the fluid could years of lube from the bearings
19 November 2016 at 12:17 #267291
duncan webster 1
Participant
@duncanwebster1
Many moons ago I had a motor with a burned out centrifugal switch. It didn't have any capacitors. I rang the UK manufacturer (Crompton Parkinson) to see if he had any spares. Turned out it was older than the chap I was speaking to, so no chance. However, he advised me that starting inrush current would be lower if it did have caps in series with the start winding, and sent me two suitable ones and a wiring diagram free of charge. That's what I call customer service. I then burgled the NVR switch so that when you had the start button held down it powered the start winding (via a relay) and the run winding via the contactor in the NVR, when it got up to speed you let go the start button and the start winding dropped out of circuit.

This is not for those who are not confident with mains electrics! If you want more sophistication, you could use a timer to fire up the start winding for a short tiime, but that's getting a bit complicated.
19 November 2016 at 18:05 #267367
Howard Lewis
Participant
@howardlewis46836
Am NOT an electrician, but it may be, as already suggested, a failed capacitor.

The one on my small air compressor failed quite suddenly; a loud bang followed by fluid leaking out. Replacement cost £6.00, a few years ago, from the local motor rewinders.

If, the centrifugal switch contacts have welded, then the Start windings will have been in circuit continuously, which they are not supposed to be. Another possible source of heat and smoke.

The motor on my Myford once gave a good show of flashes and smoke. Fortunately, the local rewinders diagnosed it as swarf across the centrifugal switch and managed to clean it up enough to continue working until after I had sold it

If in any doubt, have your local motor repairers check it out. Hopefully it will be capable of further service, after a bit of rectification.

Howard
19 November 2016 at 18:20 #267374
Brian Oldford
Participant
@brianoldford70365
Posted by duncan webster on 19/11/2016 12:17:38:. . . . . . . . .If you want more sophistication, you could use a timer to fire up the start winding for a short tiime, but that's getting a bit complicated.

Perhaps of interest is the fact I have an EU (Italy?) built Teco motor here with just such an electronic gizmo built in. I was informed by the seller that some manufacturers prefer such an arrangement as it overcomes the unreliability of the centrifugal switch. There is even the facility to alter the timing of the start winding energisation.
19 November 2016 at 19:19 #267388
sean logie
Participant
@seanlogie69385
Where would be the best source for a 1hp motor 1425/1500rpm 16mm keyed shaft ?
19 November 2016 at 19:35 #267391
mark smith 20
Participant
@marksmith20
Sean your motor shaft is probably 5/8" imperial , they cost a lot compared to the metric frame versions.

I would try and find an American motor as that is rate 110/240 v as the shaft size and probably the frame will fit.
19 November 2016 at 19:41 #267392
sean logie
Participant
@seanlogie69385
Been thinking about the shaft size, I've been looking at this

https://www.machinemart.co.uk/p/3-4in-single-phase-4-pole-motor/

I will just get 2 step pulley's to suit .
19 November 2016 at 20:15 #267396
mark smith 20
Participant
@marksmith20
Sorry mistake forgot i put a 3ph motor on so irrelevant!!!

Edited By mark smith 20 on 19/11/2016 20:21:25
20 November 2016 at 09:23 #267459
sean logie
Participant
@seanlogie69385
Disconnected cap ,motor needed help to start but ran fine . Connected cap back up motor ran nicely ,fitted it back onto lathe fired up the lathe ran fine for about 30sec then started smoking bad and tripped the electrics both motor and capacitor were very warm . Now I’m confused . New motor I think , the old one is 70yrs old so no shame to it .

Sean

Edited By sean logie on 20/11/2016 09:23:52
20 November 2016 at 10:19 #267476
Les Jones 1
Participant
@lesjones1
Hi sean,
I assume that when you ran the motor without the start capacitor by helping it to start you ran it for a reasonable time (Say 1 hour.) and monitored the temperature of the motor. (Even if this was just by putting your hand on it.) If this is the case then the fault must be the capacitor, the start winding or the centrifugal switch.( Which were not connected during this test.) You can test if the centrifugal switch is working by connecting a small low wattage mains voltage lamp in place of the capacitor. (Between 15 and 40 watts normal filament lamp.) When you apply power the lamp should light. When you have spun the motor and it is running at it's normal speed the lamp should go out. IFF the centrifugal switch is working then the fault must be either the capacitor or the start winding breaking down to earth. (It could still be the centrifugal switch tracking to earth. (I had been thinking that you had dismantled the motor but that was another thread realated to motors.) ) The centrifugal switch, capacator and start winding are wired in series between live and neutral. For the motor to work the sequence does matter but if you could trace out the sequence it may give us a way to suggest tests that you could do to decide which of the three items could be tracking to earth. Another thought has just occurred to me. It could be that when you put it back into the lathe that someting was tight in the lathe preventing the motor from getting up to speed so thet the start winding was not being disconnected by the centrifugal switch.

Les.
Author

Posts