Table Saw Power 120/240?

[DavidF]

>> Less heat in the motor and lower voltage drop means the motor is not as stressed on start up and the peak starting currents will be lower,

This is a popular misconception.

All convertible 120/240 motors run on 120 volts internally. There are two coils each running 120 volts and using 1/2 the 120 volt amperage (The coils act as a resistance and split the amperage). All you do when you re-wire the motor to run on 240 is change the wiring connecting of the coils from parallel to series. When wired for 240 volt operation, one 120 volt leg and its associated amperage is routed to each individual coil rather than a single 120 volt line providing 120 volts to both coils. The same voltage and amperage runs through the individual coils no matter how it it wired. It is amperage that creates heat, and because the amperage in each coil is the same for both wiring configuations, there is no difference in the heat produced by either wiring configuation. The motor is perfectly happy with either voltage and doesn't even know you made the change.

Surely it is the power dissipated that creates the heat not the amperage and it is also the same power dissipated through the combined coils that remains the same regardless of 110 or 220 v, but the sentiment remains the same, the saw doesn't mind either way, but I would still go with 220!

 

[cpowell]

Thanks for the info Mike, I have reached the point in my shop construction where I am installing receptacles. I put a GFCI in the box for the door opener and wired the drop cord coming from the ceiling to my center machines downstream from the GFCI I am thinking ANY protection I can give the opener electronics would be a help. I hope the plug in light exemption remains I am installing 7 eight foot flourescents all on plugs for possible future changes. I think that GFCI protection up at the ceiling is kind of overkill and I could do without the added cost of 4 more GFCIs. The lights will be wired in four banks.

As far as the fluorescent wiring, if your lighting receptacles are located on the ceiling then refer your electrician/inspector to exception No. 1 for NEC 210.8(A)(2)...Receptacles that are not readily accessible. (I am going by NEC 2005.)


Chuck