Motor problems please help

[808raver]

I was wondering if anybody knows what's happening with my table saw? I got given a fantastic old (1940-1950's) 2HP table saw. It can take a 15" blade and is a real beast but after 3 uses it started blowing a fuse on start up every time. I looked on the motor and it says 12 amp on start, seeing as the plug can only take a 13 amp fuse and given its age I put a 15 amp fuse wire where the fuse should go, this has stopped it blowing a fuse but it's still very sluggish on start and sometimes I have to give it a hand to start by turning the pulley belt.
I was wondering if it could be the motor start capacitor, it looks to be original, does anybody know if these capacitors lose power over time?

[bodrighywood]

I had this problem with an old pillar drill I had and it was a simple
matter of the bearings etc being full lof dust so kit had to pull a lot of power to get going. A good clean and it solved the problem. Could be the same? just needs a good clean inside.

Pete

[808raver]

Hi Pete
I did take the motor apart (not fully) but all seemed very clean inside, while I was there I changed some wiring that looked past it (not inside the motor but from the capacitor to the motor) , perhaps I should have taken it fully apart but I know how hard it can be taking off the pulley wheel and seeing how the connections were in a enclosed housing everything looked as clean as the day it was made.

[Paul Hannaby]

If this is the type of motor with a centrifugal switch, check that's conducting when closed. If you have a suitable multimeter, test the capacitor and if you don't, remove it to see if the motor runs the same with/without to confirm the capacitor is faulty.

[Valkrider]

I had a similar issue with my bandsaw and it was the capacitor. My replacement was cheap enough and came from Amazon.

[808raver]

Hi Paul
I'm sure it is a centrifugal switch, I can hear it disconnect as the motor slows, unfortunately I'm not good with electrics so the ammeter is out but are you saying the motor will run without the motor start capacitor connected? because that I can do lol   

[808raver]

Hi Valkrider
I hope it is just the capacitor, nice and cheap to fix I have been looking up how old the table saw is, I can't find the exact date but I suspect 1940's, it has a checked plaque from 1955 by another company so I doubt that's the date of manufacture.
It is a " Parry and sons tool manufacturers" All the rulers, angal plates, and company names are on brass plates.
Other than the motor being a little laboured it all works like it should   

[Duncan A]

Always worth fitting a new capacitor on an old motor, costs just a few quid.

However, I doubt that ST Amps is starting amps; it is more likely to be stator amps i.e. what is nowadays usually referred to as Full Load Current (FLC) - and in the case of your saw, continuously rated at 12A.
12A is about normal FLC for a single phase 230V motor but starting current could briefly be 6 to 8 times that i.e. 72 to 96A and that is almost certainly why you are blowing fuses. On my 2hp bandsaw I can get one start on a 13A fuse, but it blows upon a second attempt.
Install a proper 16A supply via  your consumer unit and a Schuko or Commando type plug and socket and you should be fine.
Your consumer unit takes Miniature Circuit Breakers (MCB), usually type B in a domestic setting. Some would recommend a type C MCB, as they are not so quick acting and deal better with the start current, but something like your saw would probably be OK on a type B.
Ask an electrician to wire it in properly, then you'll never have to worry again!
Duncan

[Paul Hannaby]

Hi Paul
I'm sure it is a centrifugal switch, I can hear it disconnect as the motor slows, unfortunately I'm not good with electrics so the ammeter is out but are you saying the motor will run without the motor start capacitor connected? because that I can do lol   

What I'm saying is that if the capacitor is faulty, the motor will do the same whether the capacitor is connected or not so you can use that as a test. The motor won't run well without a capacitor or with a faulty capacitor.

[The Bowler Hatted Turner]

I agree with Duncan A's remarks. I have just had the workshop rewired and had a similar problem with my lathe so the electrician installed a type b or c in the new distribution board. His description was exactly what Duncan has just said. I have had no problems since.

[808raver]

Thank you all,
I have ordered a new capacitor, it seems the high current draw on start and the sluggish start (even with the 15 amp fuse wire) is indicative of a non working capacitor.
I have seen someone on youtube refurbishing the exact same motor as mine and his problems were fixed by replacing the start capacitor.
Now I've seen how my motor should run I can see how bad things are with mine ATM.
I think (from the reading I have done) that once the new capacitor is fitted the saw should run without fitting a 16 amp socket, I hope it does because that will mean I can use a extension lead and all sockets in my workshop (it's on wheels)   
Thank you all for all the advice, I will update this thread once the new capacitor is fitted just incase someone else is having the same problems.
   

[808raver]

Hi All
Fantastic success, it was the start capacitor, it now runs like a dream.
I've removed the 15 amp fuse and I'm now back to a 13 amp and I've tried it on extension lead that has  a very sensitive trip button without any problem.
Thank you all again  
I will include this site on changing start capacitors as I found it very useful.
https://inspectapedia.com/electric/Motor_Capacitor_Selection.php     

[Wood spinner]

Don't you just love it when a plan comes together