phase resistors
phase resistors
(OP)
I recently ran across a motor that had been wired with a resistance wire from phase to phase on the T terminals of the mag starter. The motor is a 25hp 1750 rpm motor that was having a "slow start" issue. A 14ga wire was installed between T1-T2 and then from T2-T3. What is it's purpose and why would that solve a voltage drop situation?





RE: phase resistors
If it is a KUSA, it works by connecting two motor phases to the grid and one via the resistor. That reduces current because stator voltage is reduced and at the same time a (reduced) rotating field is produced by the resistive path to the third winding. When the motor is running, the third phase is connected directly (resistor shorted).
It cannot be used on constant torque loads (conveyor and such) but works very well on fans and other high-inertia loads.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: phase resistors
Bill
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"Why not the best?"
Jimmy Carter
RE: phase resistors
RE: phase resistors
Are there 6 leads out of the motor?
When I see three terminals jumpered, I would think its the wye point of the motor winding.
RE: phase resistors
RE: phase resistors
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...