[TheForge] Third HP motor problem

[Richardson, Grover]

Yes, Mr Brewer is correct.  The switch is spin activated.  Usually mounted on the end of the motor where the wires come into the motor.  Yes, dust and stuff can get in there and cause it to not actuate properly.  The hum but will work when spun is a classic symptom of "starter winding" problems.  If you replace the original capacitor that is within 50% of the value of the original capacitor, it should crank, though it may not be happy.  A good test to see if your capacitor is bad.  If a known good capacitor doesn't start the beastie, then the spin switch is the next likely culprit.

DANGER WILL ROBINSON---there are dc capacitors and ac capacitors.  ONLY use an ac capacitor rated at least 300 VAC for a 110 V line.  Dc capacitors become small grenades when subjected to ac.

All the best

-----Original Message-----
From: TheForge [mailto:theforge-bounces at mailman.qth.net] On Behalf Of Dan Brewer
Sent: Wednesday, December 03, 2014 9:36 AM
To: Blacksmithing List Sponsored by ABANA
Subject: Re: [TheForge] Third HP motor problem

I would replace the capacitor.  Lots things go wrong with them  that do not show up as physical damage.  You will also want to use compressed air or a vaccume to remove any acculiated stuff from the motor.  If you have the motor apart new grease for the bearings.  There is a small switch in some of the motors that put the capicator in to the mix and then takes it out when the motor reached speed.  Some times the switch gets stuck.  This is where the cleanning comes in.  Look for burned wires or broken connections also.
Dan in Auburn

On Wed, Dec 3, 2014 at 6:06 AM, Ron Childers <ron at munlaw.net> wrote:

> Small Delta belt grinder 1/3rd HP motor just hums but will finally run 
> if the pulley is spun. The capacitor looks ok but we tried another 
> although it's a higher MFD- I think it should run if the windings are 
> ok. Probably no hope for the motor but the grinder is still ok. Any ideas?
>
> -----Original Message-----
> From: TheForge [mailto:theforge-bounces at mailman.qth.net] On Behalf Of 
> David E. Smucker
> Sent: Tuesday, December 02, 2014 7:12 PM
> To: 'Blacksmithing List Sponsored by ABANA'
> Subject: Re: [TheForge] Harbor Freight quality
>
> Don't read horse power -- read run current (amps) and voltage.  
> Remember that it wasn't China that started this "hoorse power crap" 
> but Sears.  (2 horse power "American motors" put out no more work than 
> any other country's motors rate in current and amps.
>
> Dave
>
> -----Original Message-----
> From: TheForge [mailto:theforge-bounces at mailman.qth.net] On Behalf Of 
> Richardson, Grover
> Sent: Tuesday, December 02, 2014 3:14 PM
> To: 'Blacksmithing List Sponsored by ABANA'
> Subject: Re: [TheForge] Harbor Freight quality
>
> The main thing I tell my folk is to remember the motors.  A 2 
> horsepower American motor will put out 2 horsepower of work.  A 2 
> horsepower China motor is 2 horsepower lock rotor.  They take a vise 
> grip (philosophically
> speaking) and hold the shaft, and apply power.  The power that enters 
> the motor under "locked rotor" conditions, ie worse case, is the 
> horsepower of their rating.  At best I figure a 2 hp China motor will do 1/2 to 3/4 hp.
> So when using my Harbor Freight chop saw, I load it down until I hear 
> it slow down in rpm, and do a slow cut.  Had it over 10 years.  Used 
> up at least 6 blades on it so far.
>
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