Miscellaneous
MST03
Microprocessor-Controlled Motor Drive for Precise Operation of Motorized Variacs with DC Motors up to 30 W
Art.-Nr.: 9578
1. Special Properties
The MST03 motor controller can process either AC (sine wave) or DC voltage feedback signals. Switching between modes is done via jumper J2 and a corresponding software setting.
AC voltage feedback is measured using a voltage transformer (galvanically isolated). Fine adjustment of the AC feedback is performed via potentiometer R26.
DC voltage feedback (0–10 V) is processed without galvanic isolation or rectification. Fine adjustment of the DC feedback is performed via potentiometer R23.
Motor speed and direction are controlled via an H-bridge. Maximum current: Iₚₑₐₖ = 5 A. The DC motor supply voltage can be either 24 VDC or 12 VDC.
Setpoint input is provided via PC using an RS232 interface or via an external 10 kΩ potentiometer (0–10 V) connected to X5.
The controller includes end-position detection, which connects to the limit switches of the variac.
Additional adjustments are available via potentiometers R60–R67:
- Definition of control zone size
- Voltage deviation (hysteresis)
- Motor speed inside and outside the control zone
- Control amplitude setting
- Adjustable maximum voltage limit
- Jitter pulse to prevent wiper contact sticking
- Wire break protection: variac moves to either 0 V or maximum voltage
All settings are visible on the display.