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Ned Simmons

On 6 Sep 2007 01:18:15 GMT, (DoN. Nichols) wrote:

According to DanG :

[ ... ]

For those who asked:

The motor is a Leeson
1.5 HP
90 volt
15 AMP
4800 RPM
The output shaft is NOT threaded - normal flatted shaft.
It does say Torque 19.7, I've not seen this before and I am
curious what this one means.

At a guess -- DC PM motors often have a limit on the current
which can pass through them before it starts to demagnetize the
permanent magnet fields.

The current in a DC motor is proportional to torque.

So this is probably the maximum safe torque (probably
corresponding to the 15A spec). At a guess, that is foot pounds, but it
could be inch pounds, or Newton Meters without units from the data
place.

HP = in*lb x RPM / 63,000

1.5HP = 19.7 in*lb x 4800 RPM / 63,000

So except for the fact that the units are not shown, the torque number
is redundant.

Demag current on this sort of motor is usually around 3x rated
current, it can be as high as 7x for fancy motors with expensive
magnets.

--
Ned Simmons