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Vol. 2.6 © 2020 Hanbell Precise Machinery Co., Ltd. All rights reserved
Motor temperature
The motor temperature is constantly measured by thermostat (PTC) loop connected on
S1-S2. If detected temperature exceeds setting its resistance will increase above the trip
point then the output relay trips (M1-M2 is open). After cooling down below the response
temperature, 5-minute delay is activated. After delay has elapsed, the relay pulls in again
(M1-M2 is closed).The time delay can be cancelled by main reset of approx. 5 seconds
(disconnect L-N).
Other major functional descriptions are as below:
1. After the supply voltage has been connected, a three second initialization period follows.
Provide the PTC chain resistance is below the reset threshold (2.75k
Ω
), the relay trips
after these 3 seconds have expired.
2. 1 to 9 PTC thermostats with different nominal response temperature may be connected
serially to the PTC input.
3. If any thermostat resistance increases above trip level the relay drops out. This failure
results in a lockout. (5 minutes delay for 1st PTC failure, 60 minutes delay for 2nd failure,
lockout for 3rd failure.)
4. If a rapid temperature increase is detected (locked rotor condition), the output relay
drops out. This failure results in a lockout.
5. The phase monitoring of the three phase motor voltage becomes active 1 second after
motor has started, for duration of 10 seconds. In case of a wrong phase sequence or a
phase failure, the relay switches of and locks.
6. The Lock-out and delay time may be lifted by cycling the power off for approx. 5
seconds.
7. To avoid nuisance tripping due to reverse running after shutdown (pressure
equalization), the phase monitoring function is only re-enabled approx. 20 seconds after
motor stop.
8. A dual LED (red / green) provides additional information about the motor protector and
compressor status.
9. The relay is fed out as an N/O dry contact, which is closed under good conditions.
10. Sensor and supply circuits are galvanic isolated.
11. The motor protector is not suitable for application of frequency converters.
