RANSBURG LECU4013-00 P.C.BOARD ASSY,MOTOR CONTROL
The LECU4013-00 Motor Control PC Board Assembly receives the 0-10VDC KV feedback signal from the power supply through wire #34. This signal is compared to the requested KV set point signal supplied from the control unit front panel or from a remote source. The resulting error signalis used to drive the bi-directional motor, that is connected to the variable transformer (VAT1) shaft,in the direction required to produce the requested high voltage.A limit switch, located in the box that surrounds the variable transformer, rides on a cam that isattached to VAT1. The cam will activate the limit switch in the “home” position and in the “over-voltage” position. The motor control board will always rotate VAT1 counterclockwise to the “home”position when KV is turned OFF or AC power is supplied to the control panel. It is important to note that the overload inhibit timer is activated only on the HV ON command signal and not at the point where VAT1 starts from the “home” position. Therefore, if a HV ON command is given BEFORE VAT1 has had a chance to reach “home”from a previous HV OFF or overload reset, theinhibit timer may elapse before VAT1 can reach the “home” position and return to the HV setting.This may cause an overload to occur since the overload timer elapsed before the system has had a chance to initially charge.The Motor Control Board will cause a power supply overload in the event of an over voltage condition or if there is a loss of the power supply feedback signal.
