PERMANENT MAGNET GENERATORS ALTERNATEURS A AIMANTS PERMANENTS

PILOT GENERATOR

D
EFINITION The pilot generator ensures the supply of the voltage regulator of the main generator. It is wedged on the main generator shaft. D
IAGRAM -M
ODE OF RUNNING : The skeleton diagram, as mentioned below, shows the conventional application of the P.M.G. pilot generator.
1 : Main generator 2: Stator 3: Exciter field winding 4: Voltage regulator 5: Control unit 6: Power unit 7: Industrial circuit breaker 8: Current transformer for parallel operation 9: Voltage actual value measurement 12: Permanent Magnet Generator The pilot generator (permanent magnet) ensures the supply of the voltage regulator. This voltage regulator compares the network voltage with the reference voltage. It delivers to the field system of the exciter, the current required in order to maintain the main generator voltage at its rated value. When the load changes, the voltage of the main generator terminals changes as well. The regulator reacts in order to oppose the voltage change : the required power is supplied by the P.M.G. When load changes suddenly, it is necessary to quickly supply a large current to the field system, so the P.M.G. supplies its overload power during a few seconds. Then the regulator will deliver the over-excitation current required for the field system of the exciter to reset the voltage of the main generator to its rated value. A
DVANTAGES OF THE P
ILOT G
ENERATOR Excitation systems of generators including a pilot generator have a more simple and more rational design than the compound excitation systems and provide to the set a larger reliability The characteristics of the pilot generator : rated power, overload power, no-load voltage, rated voltage, overload voltage, are a function of the excitation performances required by the main generator : maximum admissible drop voltage - response time - short-circuit holding.
PMG-ATR-0308A-En