PURPOSE: To avoid overshoot and eliminate the need for adjustment operation.
CONSTITUTION: Amounts of deviation between radial seal gap detected by a sensor and a desired gap value are detected by means of a drive control circuit 52. The circuit 52 has an average voltage in proportion to the amounts of deviation and delivers a speed command signal 53 which decreases in a certain period of time, and delivers a normal rotation command signal 54 or reverse rotation command signal 55 depending on positive or negative sign of the value of deviation. These command signals are given to an inverter 51, whereupon the inverter 51 varies the frequency of a drive power source for an induction motor 7 for a sector plate driver of a seal gap control device of a rotary regenerative heat exchanger according to the command signals. By this method, the motor 7 rotates at rotational speeds corresponding to the amount of the deviation and the rotational speed gradually decreases in a certain period of time.
HASEGAWA TOSHIAKI
TAMASHIMA KUNIHIKO
