Brian Roth
Well-known member
I received a clear reply from Jay McKnight (long time Ampex guru and owner of MRL alignment tape company):
Hello Brian,
On "speed" -- could you please send them a note that a discussion of "speed" can
be found in my paper at http://mrltapes.com/mcknight_speed.pdf .
On "sync" motors: Both non-sync and sync motors are fake two-phase "induction"
motors. One phase is connected directly to the power line. Because the winding
is an inductor, the field in that phase will be 90 deg out of phase with the
power line. The other phase is in series with a "run capacitor", sized to produce
resonance with the inductance of that winding, therefore the field is in phase
with the line voltage. Thereby the two windings are 90 deg out of phase, making
a two-phase motor.
Whether is makes a sync motor or a non-sync motor depends on the construction of
the rotor, The details are in the Wikipedia article online
"hysteresis-synchronous motor".
Jay McKnight
Hello Brian,
On "speed" -- could you please send them a note that a discussion of "speed" can
be found in my paper at http://mrltapes.com/mcknight_speed.pdf .
On "sync" motors: Both non-sync and sync motors are fake two-phase "induction"
motors. One phase is connected directly to the power line. Because the winding
is an inductor, the field in that phase will be 90 deg out of phase with the
power line. The other phase is in series with a "run capacitor", sized to produce
resonance with the inductance of that winding, therefore the field is in phase
with the line voltage. Thereby the two windings are 90 deg out of phase, making
a two-phase motor.
Whether is makes a sync motor or a non-sync motor depends on the construction of
the rotor, The details are in the Wikipedia article online
"hysteresis-synchronous motor".
Jay McKnight
