bceng87SS1517
Electrical
Looking for information on synchronous motor exciters, specifically any books or white papers that review the output waveforms of various packages or anything with good information.
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Synchronous motor exciter
- Thread starter bceng87SS1517
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Waveforms will be the standard 6-pulse controlled rectifier (or maybe 12-pulse if it's a really big one) operating into a highly inductive load. The rectifier will be either a half-controlled bridge or fully-controlled bridge: being honest I've never seen a fully-controlled bridge used to drive the field of a synchronous motor, but they're not uncommon on synchronous generators. Any half-decent power electronics text should cover both half-controlled and fully-controlled bridges in reasonable detail.
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Google "polarized field frequency relay"
Link
The Electric Machinery Company developed and patented the first polarized field frequency relay over 100 years ago.
For many decades the polarized field frequency relay did the job of applying the field safely to a synchromous motor when the following conditions were met.
1. The speed was high enough to permit the motor to pull in to step.
2. The rotor angular position of the rotor was acceptable for a smooth pull in.
The operation of the old polarized field frequency relay is fairly easy to understand. A familiarity of the original basic relay may help to understand how the new electronic field relays work with the brushless excitation systems.
It may also help to explain the significance of the offset waveform that facilitated the operation of the polarized field frequency relay.
When the rotor is stationary and the stator is energized, transformer action induces an alternating voltage in the rotor.
This voltage caused the armature of the relay to pull in. As the rotor accelerates, this induced AC decreases in both voltage and frequency.
The DC coil causes an offset in the flux in the relay core. The offset causes the relay to drop out when the phase angle is good for smooth pull in.
The relay has a set of normally open contacts that energize the field when the relay drops out.
Bill
--------------------
"Why not the best?"
Jimmy Carter
Link
The Electric Machinery Company developed and patented the first polarized field frequency relay over 100 years ago.
For many decades the polarized field frequency relay did the job of applying the field safely to a synchromous motor when the following conditions were met.
1. The speed was high enough to permit the motor to pull in to step.
2. The rotor angular position of the rotor was acceptable for a smooth pull in.
The operation of the old polarized field frequency relay is fairly easy to understand. A familiarity of the original basic relay may help to understand how the new electronic field relays work with the brushless excitation systems.
It may also help to explain the significance of the offset waveform that facilitated the operation of the polarized field frequency relay.
When the rotor is stationary and the stator is energized, transformer action induces an alternating voltage in the rotor.
This voltage caused the armature of the relay to pull in. As the rotor accelerates, this induced AC decreases in both voltage and frequency.
The DC coil causes an offset in the flux in the relay core. The offset causes the relay to drop out when the phase angle is good for smooth pull in.
The relay has a set of normally open contacts that energize the field when the relay drops out.
Bill
--------------------
"Why not the best?"
Jimmy Carter
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