5 | electrical connection – GEA Bock HG12e CO2 User Manual
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96282-02.2015-DGbFEI
5| Electrical connection
PTC1
PTC2
Terminal box
Fig. 18
Temperature monitoring connections:
Motor winding:
Terminals 1 - 2
Thermal protection thermostat:
Terminals 3 - 4
Restart prevention:
Terminals 5 - 6
5.4 Electronic trigger unit MP 10
The compressor motor is fitted with cold conductor temperature sensors (PTC) connected to the 
electronic trigger unit MP 10 in the terminal box. Readiness to operate is signalled by the H3 LED 
(green) after the power supply is applied. In the case of excess temperature in the motor winding, the 
unit switches off the compressor and the H1 LED lights red.
The hot gas side of the compressor can also be protected against overtemperature using a thermal 
protection thermostat (accessory). The H2 LED (red) is provided for the protection function.
The unit trips when an overload or inadmissible operating conditions occur. Find and remedy 
the cause.
5.5 Connection of the trigger unit MP 10
ATTENTION
Terminals 1 - 6 on the trigger 
unit MP 10 and terminals PTC 
1 and PTC 2 on the compres-
sor terminal board must not 
come into contact with mains 
voltage. This would destroy the 
trigger unit and PTC sensors.
The supply voltage at L1-N 
(+/- for DC 24 V version) must 
be identical to the voltage at 
terminals 11, 12, 14 and 43. 
INFO
 The	unit	has	a	restart	prevention	device.	After	you	have	rectified	the	
fault, interrupt the mains voltage. This unlocks the restart prevention 
device and the LEDs H1 and H2 go out.
INFO
Connect the trigger unit MP10 in accordance with the circuit dia-
gram. Protect the trigger unit with a delayed-action fuse (F) of max. 
4 A. In order to guarantee the protection function, install the trigger 
unit	as	the	first	element	in	the	control	power	circuit.
