Micropump DB-380.B - Manual (Page 10)

10 of 20 MODEL 380 MOTOR INSTALLATION AND OPERATION MANUAL IOM # 7820
REV A
(10/99)
MICROPUMP, INC.
A Unit of IDEX Corporation
PO Box 8975, Vancouver, WA 98668-8975, USA
Phone: (360) 253-2008
Fax: (360) 253-2401
email: [email protected]
Website: www.micropump.com
MICROPUMP LIMITED
A Subsidiary of Micropump, Inc.
Howard Road, Eaton Socon
St. Neots, Cambs. PE19 3ET England
Phone: (44) (0) 1480-356900
Fax: (44) (0) 1480-356920
Website:
www.micropump.com
A program which includes periodic monitoring of your Micropump
pump is recommended in order to provide timely detection and
assessment of any problems.
Flow rate should always be adjusted by a diverter valve fitted in the
discharge line or the motor speed. NEVER throttle the flow of a
positive displacement pump by the inlet valve.
•
Check that the pump and motor operate smoothly and are free from excessive vibration or cyclic noise.
•
Check the inlet and discharge fittings are free from leaks.
Shut-down Procedure. To shut down the Model 380 drive, first, turn off the control voltage. Check that the unit runs down in a
steady manner. When the unit has stopped, disconnect the 24VDC power. Close the inlet and discharge valves. Drain the pump if
it is to be shut down for long periods or installed in areas where the liquid may freeze.
If a low impedance path (i.e. a solenoid valve) is connected in
parallel with the motor power leads and the 24VDC power is shut
off before the motor stops, potentially damaging regenerative
currents can flow out of the motor leads. Ensure motor stops before
disconnecting power.
Using the Tachometer Output. The tachometer output can be monitored using any frequency counter. The tachometer output is 0-
5V square wave that has two cycles per drive revolution. The frequency range is 0-160Hz. To convert the tachometer output to
RPM, multiply the frequency by 30. The tachometer can be used as a speed feedback in a control system, or as a means of
automatically sensing a decouple condition. Please contact your distributor if you need assistance.
How to Recognize Magnet Decoupling. Magnet decoupling occurs when the load on the pump exceeds the coupling torque
between the magnets. The magnets are forced out of pole-to-pole alignment and are decoupled. When decoupling occurs, the
driving magnet speed increases to motor no-load speed while the driven magnet and pumping parts remain motionless. An
automatic system can detect decoupling by monitoring the tachometer line and either flow or pressure. If the tachometer line is
sensing that the motor is turning but there is no flow, or pressure is much lower than expected, then a decouple is likely to have
occurred. Depending on the complexity of the control system, a warning can be issued or an automatic re-coupling routine can be
performed.
Decoupling is an inherent feature of magnetic couplings and DOES
CAUTION
NOTE
NOTE
CAUTION