MYDAX 1M9W-S, Инструкция по эксплуатации и техническому обслуживанию

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Mydax, Inc. 1M9W-S Water Cooled Chiller
Lawrence Berkeley Laboratory 3
System Electrical Diagram
Refer to drawing #B2344, the system electrical diagram. The central component of the electrical system is the M1001
controller. It is microprocessor-based and communicates with and/or controls various other circuit boards and
components. Most controller circuitry is laid out on circuit boards mounted in the main control cabinet. The controller
is powered as long as the system circuit breaker is set, receiving 24 VAC power from a bulkhead-mounted transformer.
The controller "reads" the RTD's in the system via board M1002. RTD's are included for the recirculating output
temperature and the reservoir, as well as for the freon circuit. Also routed through this board are the 100 and 120 •
precision RTD calibration resistor circuits. The evaporator valve drive signal is routed through board M1004, as is the
phase detector circuit.
The system interlock loop is controlled by the M1002 circuit board. In this application the interlock loop consists of the
freon high pressure switch, the tank over-temperature switch, the TANK EMPTY level sensor, the RESET momentary
switch, one power relay coil and a relay pole (1R 5-8). The RESET switch serves to feed power to the relay, which
energizes the contactor. When energized, the contactor feeds power back to the relay so the RESET switch may open
up without cutting off power to the relay. If the freon pressure switch, the over-temperature switch or the level sensor
trips, power to the loop is interrupted. The microprocessor senses this via the M1002 board. Provided the system has
power, if the loop trips out, the controller drives the PUSH RESET error message. The loop must be reset when the fault
condition is resolved.
The M1002 board also routes signals for the FILL TANK level sensor. If this sensor trips, the microprocessor drives
the FILL TANK error message.