? capacitor problem - advice needed.

[SimonT]

Hey guys,

Not fully sure on the workings of capacitor on a lathe, other than it gets the motor upto speed (I think ?).
Ive noticed recently my lathe struggles to turn on starting up, spins slowly. Can be sped up with a helping hand but I want it fixed really. It started off spinning slow then starting up after 30 seconds plus, now it wont spin fast at all until you turn it by hand. Am I right is this the capacitor? I have a draper wtl90 which I love so would really like to fix it if possible, am sure I can get a capacitor but hoping its not the motor.

Thanks in advance

Simon

 

[CHJ]

If it runs OK once spinning but with low power, (easily stopped) then associated with the other symptoms then 90% certain it's the capacitor, at a cost usually under £5 it's a an obvious move.

Just make sure you purchase one that is Run Rated as opposed to Start Rated as these motors need them in circuit all the time to provide a simulation of a 3rd phase to increase running torque.

 

[SimonT]

Brilliant thanks, it spins lovely when its going but slow to start, and yes actually come to mention it it does slow a little now too when turning. Thanks. Was really hoping it was noting major. Im still fairly new at turning (on/off for 2 years) and this lathe has changed how I turn massively.

Plus the fact that its about £5 to fix will keep the wife happy lol

 

[Grahamshed]

Plus the fact that its about £5 to fix will keep the wife happy lol

Always worth trying to do. Stores up brownie points for when needed

 

[SimonT]

Definitely a bonus grahamshed, extra points for when I need a new bowl gauge I guess. Anybody know whether there easy to fit / replace?

 

[CHJ]

Disconnect machine from mains.
Remove capacitor housing cover.
Disconnect the two wires from existing capacitor, or cut them off leaving usable tails coming out of motor housing.
Reconnect new capacitor either with existing spade terminals or some chocolate strip. Does not matter which way round terminals are connected.

When buying replacement, electrical size is not critical within a few Mfd. but working voltage needs to be as high or higher than existing unit. (will be something like 20mfd- 400 volt) make sure item selected will physically fit in existing housing.

 

[SimonT]

Thanks chj, sounfs simple enough. I've found the original capacitor online its about £11 Inc vat so might just go with that. Going to ring draper first though as I need some other bits too and they were very helpful last time and directed me to a cheaper supplier.

 

[Robbo3]

Having the same lathe I also experienced similar symtoms. My capacitor came from Sourcingmap on Amazon for £3.14
- http://www.amazon.co.uk/CBB60B-Round-Mo ... rds=CBB60B

I also renewed both sets of pulleys for about £30 from Axminster power tools. They are not listed on the web site so enquire by phone or email.

HTH

 

[Grahamshed]

You learn something every day on UKW

 

[SimonT]

Cheers robbo, I enquired to draper about the pulleys. Who told me they do still have them (newly ordered) for another model, but they were more than 30!!!! Lol I thinl they were 36 just for the motor pulleys. Thanks for the tip I will source a new capacitor there, I preasume it fot under the cover fine? So did your lathe act like mine or did it misbehave on a different way?

 

[SimonT]

Sorry I didnt read it peoperly, ive just seen it had similar symptoms lol

 

[SimonT]

Having the same lathe I also experienced similar symtoms. My capacitor came from Sourcingmap on Amazon for £3.14
- http://www.amazon.co.uk/CBB60B-Round-Mo ... rds=CBB60B

I also renewed both sets of pulleys for about £30 from Axminster power tools. They are not listed on the web site so enquire by phone or email.

HTH

2 more questions and ill stop I promise lol

1) Is this the actual capacitor you changed yours for as mine is rated at 10 uf the one on the link is 8uf will this matter? Chj you mentioned a little variance is fine, do you think 2uf difference would matter?

2) also chj mentioned that it didnt matter which way round they are fitted, but ive noticed some are positive/negative and some are non polar again does this matter on the type I get for my lathe or will I be ok replacing mine for a non polar version?

Sorry for all the questions but I have never replaced one before and the YouTube videos are a little contradictory.

Thanks

 

[CHJ]

Capacitors intended for AC power use do not have a polarity, case should have 250 to 440 volt ~AC on the rating.

Mfd Tolerance on these devices can be quite wide, 20% not being uncommon, so a few MFD either way is not critical.

Although an 8Mfd capacitor will provide a starting phase shift boost to the start/run winding to get the motor spinning it may not provide as much current (power) for running conditions. (who knows where it is in the tolerance stakes)

If a capacitor is marked with polarity +/- then it is most likely an electrolytic type designed for use on DC power supplies for smoothing and storing energy.

 

[Robbo3]

1) Is this the actual capacitor you changed yours for as mine is rated at 10 uf the one on the link is 8uf will this matter? Chj you mentioned a little variance is fine, do you think 2uf difference would matter?

Thanks

I took the information off the old capacitor ie CBB60B 8Uf, & replaced it with the one that I linked to. It was a straight swap.

 

[Dalboy]

Remember that when replacing capacitor that they may not be genuine parts, they may have already been replaced. This really only applies when you have brought a second hand machine.

 

[SimonT]

Remember that when replacing capacitor that they may not be genuine parts, they may have already been replaced. This really only applies when you have brought a second hand machine.

Fair point, I hadnt really considered that factor to be fair. Having looked at it im not sure if its been replaced or not.

If that capacitor works for yourself robbo3 I think I'll just get that one, you had no issues with it running slow / lacking power since youve changed it I presume?

Thanks everbody, been really helpfull.

 

[CHJ]

I've used this source in the past.

A check on the company Shop will show their current stock.

If you have a local Maplins they may have suitable item.

 

[SimonT]

Cheers chas, just ordered the one robbo3 recomended as he has the same lathe, but of all else fails ill try them. I thought for 3.14 its worth wasting the money to try, as from what ive read as long as the voltage is ok it wont hurt having a lower microfarads (as you said), worst that will happen is it wont work right ? Lol seeing as it doesnt anyway all ive wasted is a couple of quid.

 

[Jonzjob]

A couple of weeks back I had a motor, my ex Record single phase motor, fail to start. I checked the capacitor and it seemed OK.

There is a set of centrigugal contacts on the rotor that drop the cap out once the motor is spinning. I stripped the end plate off the motor and checked and cleaned those contacts. They were dirty. I cleaned them with a special diamond contact cleaner, but there's no reason they can't be cleaned with some fine, say 400 grit, abrasive.

Every time the motor is strated those contacts will arc when they open. Eventually they will pit and will not close properly and you have the same symptom as a blown cap.

The job took me about 10 minutes. If you aren't competent to do the job then just take the cap to your local motor repair place and they will check it for you. If it is OK then they will check the contacts for you too if they are any good.

 

[SimonT]

Thanks john, I hadn't thought about that but will give it a try tomorrow. I have ordered the capacitor but its only pounds anyway.