I don't think anyone would expect to be able to get the suggested clock
motor to do any real work, Bill.

As I mentioned earlier, there are many split-phase motors that are
built/manufactured without start capacitors, which operate properly in their
intended applications (low or no starting load).

Simply put, capacitor start split-phase motors have greater starting torque
than an equivalent non-capacitor start, split-phase motor, for applications
where a load is present at startup.

When most of us want to power a project machine, the main considerations are
voltage, speed and motor output.
For many, assuming that bigger is better, one could use 5HP motors for
almost all of their shop machines.

I've encountered situations (powering small machines with spare motors)
where an adequately sized motor wouldn't start occasionally, and by adding
a suitably sized start capacitor to a non-capacitor start, split-phase motor
would increase the starting torque to the point where the machine would
start perfectly.
That, to me, is an advantage, in that I didn't need to go find/buy a higher
output motor.
I suspect that many others would have assumed that the motor was inadequate,
and gone looking for one with higher output.

This same example would be advantageous to a manufacturer, when specifying
motors, to select capacitor start, split-phase motors for more starting
torque instead of choosing a higher output motor (higher cost and weight,
greater energy consumption etc).

I don't understand what you were trying to say with your last sentance.

The start winding dictates which direction a split-phase motor will spin up.
I'm fairly certain that all of the split-phase motors I've enountered will
*run* in either direction, except that some motors are only provided with a
wiring tap for a single direction, but if one chose to start their
split-phase motors manually (eliminating the start winding circuit
altogether), the motors would operate equally well in either direction.

The capacitor(s) (start or run) in split-phase motors have nothing to do
with rotational direction, according to anything I've read in motor books.

--
WB
..........
metalworking projects
www.kwagmire.com/metal_proj.html


"Bill Noble" wrote in message
...

"Wild_Bill" wrote in message
...
I trust you are correct, Bill. Perhaps a better choice for a word to
replace (the) *purpose*, would be (the) advantage
... of the capacitor in the motor's starting circuit is to increase
torque during startup

--
WB
.........

close, but still not quite right - for example, take an old time clock
motor (really old time - like 1930) - many of these will run either way
and there is a little knob to twist to start them in the right way - if
you do nothing, they sit there and buzzzzzzz. spin the knob and off they
go. So, the start windings on your larger motor are like this little
knob - they produce a rotating magnetic field, like a 3 phase motor. To
do this, you need to get the phase angles, and that is where the capacitor
comes in. It forms an LC (inductance/capacitance) circuit with the coil
and that creates the phase shift.

So, yes, the start winding increases torque, and the capacitor gives the
phase shift so it will turn and in the right direction