Table Saw keeps blowing 20 amp fuse. It is a Central Machinery table Saw, with a 2 hp motor wired for 110vl?

Question

I have been using it successfully for 6 years plugging it into my outlet that I use for the washer( not running). It just started blowing 20 amp fuses when I start it up. It will run without the belt so I checked the belt alignment and it was correct and no binding. Any ideas why it started to do this and how I might correct it.

Thanks

Answer 1

I have run a 2HP compressor on a 20 amp circuit for many years. A compressor takes a lot more power than a saw except when you are cutting some heavy duty things.

Are you plugging it directly into the outlet or through an extention cord? If a cord, how long and what guage? Cord should be a minimum of 12 guage and not terribly long. The longer and the smaller, the more the voltage drop. Motors hate voltage drop, they require more amps.

Many 2HP motors can be rewired for 220 volt. That cuts the current about in half. Check the saw's instructions.

Is there anything else on the same circuit? If so, try turning everything else off.

Answer 2

if the motor runs with no problem on its own..the check the blade assembly and see if you can turn it freely..if the blade turns hard then you will either have to replace the ball bearings..if its sleeve bearings thenoil them...grab the pully on the blade shaft and see if you can find sloppy movement inyour bearings...with motor unplugged..grab the pully on the motor and check to see if its sloppy or turns hard...it could also be a bad capacitor..bad centrifical switch or the start ...windings are not kicking out fast enough causing high amp draw...you might have to take it to a motor repair shop...you could also have a weak circuit breaker..

Answer 3

What kind of shape are the bearings for the blade in?  Are you using the same cord or a lighter one?  It's possible that with use and age the motor is starting to draw more current.  Try running a heavier cord to minimize voltage drop.  If that doesn't work, you may need to get the motor rebuilt or replaced and/or new bearings for the arbor on the table.  Hope this helps.

Answer 4

The current may be exceeding 20 amps for only a second or so while the motor is getting up to speed. You should be able to buy a 20 amp fuse that blows slower than normal. If my memory is correct, I think they're called "slo-blo" fuses.

Answer 5

You've been lucky for the past 6 years.

According to (2005) NEC Table 430.248, the full load current for a 2 HP, single phase motor is 24 Amperes. The "locked-rotor" current required at start up can be as high as 144 Amperes; but this is only for use when selecting a disconnecting means or motor controller.

Remember, most single phase, 120 Volt motors require overcurrent protection of 115% , and there is a Code requirement is that the conductors supplying the motor shall not be rated for less current than that at which the overcurrent device is set to trip (Article 430.224)

A 2 HP motor would require overcurrent protection of 27.6 Amps. You would use the next size standard breaker per Article 240.6; that would be 30 Amps, and would require #10 AWG THHN conductors per Table 310.16 & Article 240.4.