Subject: Re: tablesaws how much amperage?

From: BigJim <[email-masked]>
Date: Thu, 27 Mar 1997 09:55:29 -0900

A "rule of thumb" used in industrial applications is that the sum of the
nameplate amperages shoukd not exceed 80% of the breaker capacity.
Therefore, a 20amp breaker should not be loaded past 16 amps.  It is *not*
coincidence that most homes have 20amp breakers and there are many tools
which draw around 15 amps, yet relatively few drawing in the 16-19 range.
At that point they usually make a jump to the mid-twenties (getting near
the 80% rating on a 30amp breaker). :):)

I hope this helps.

Jim aka BigJim

At 11:10 AM 3/25/97 -0700, you wrote:
>My Delta runs fine on a 20 amp 115 volt circuit.  The motor says it is 14
>amps, 1.5 HP.
>
>ROBMURR <[email-masked]> wrote in article
><[email-masked]>...
>> I want to purchase a Jet or Delta contractor saw. I need to know
>> if either of these will run OK on a 20 amp curcuit. Nothing else is
>> on this curcuit in the garage and I would like to use it or should I
>> increase it to 30 amps?This would be on 115volts. My 100amp
>> breaker box is full already...what is my least expensive and least
>> extensive solution? thanks!
>>
>>
>
>

---

From: [email-masked]
Date: 28 Mar 1997 05:05:51 GMT

Christopher Raymond wrote:
>p.s.  I'm guessing here, but I think the dual capacitor motor is only
>helpful for startup - the caps are switched out of the circuit once the
>motor is up to speed.  Anybody know for sure?

Here is my Delta CS motor FAQ

A single phase induction motor uses the start capacitor to produce the 90
degree phase shift for a second winding in the motor. The motor acts like
a two phase motor until it reaches about 75% of full speed when the
centrifugal switch opens and removes the start capacitor (and second
winding). If the centrifugal switch is stuck open (or the capacitor is
bad) the motor will not start until you spin it up by hand. (This maybe OK
on a drill press but don’t try this on a table saw.) A Capacitor-start
motor can provide a starting torque 3 to 4 times the full load torque.
(Fractional horsepower motors may not require this torque so they may use
other starting methods.)

The Delta CS has a Capacitor-start Capacitor-run motor, you can see the
two capacitors on the side of the motor. In this type of motor the second
winding is never disconnected from the power line. Both capacitors are
connected for starting but when the motor reaches 75% speed only one
capacitor is disconnected. The smaller run capacitor as always connected
the second winding. A Capacitor-run motor has a higher efficiency and a
higher pull-out torque than a motor with just Capacitor-start. The power
factor is nearly 100%.

This may not be the gospel but I did study motors and generators under
Father Wood at Seattle University. I pray that I got this right.

Michael Holley