ABB C011 Instructions De Service Et De Montage page 3

lnsulation test
In opposition to the surrounding material the temperature sensors are insulated for an operational voltage of about 600 V.
The insulation with respect to the winding and casing should be tested after impregnation and drying. Before the test is performed all
leads to temperature sensors should be interconnected.
Test voltage in accordance with VDE 0530, 12.65.
The test voltage has to be applied between the sensor connections and the motor winding.
Resistance test of built-in temperature sensors
Before and after impregnating the windings, test the resistance the series temperature sensors. If the reading obtained is < 250 ohm
per sensor, the sensors and leads are correctly installed (when several sensors are in series, the permissible resistance increases with
the number of sensors). For this measurement a method should be used in which the voltage drop per sensor is not more than 2.5 V,
e.g. Wheatstone bridge or multi-purpose instrument with a resistance scale.
Installation of the temperature sensors
The sensors are inserted in the stator coils nearest to the rotor, before the winding is impregnated.
In enclosed machines the sensors should be embedded in the middle of the end-coils so that they are completely surrounded by
winding wires. Before insertion the sensors should be dipped in synthetic resin. When they have been inserted, this point should
be taped before the resin sets. In each leg of the winding one sensor should be inserted, with its lead-in wires parallel to the coil
conductors. The sensors are connected in series, connected up, insulated, and, finally, to avoid tension on the leads, they should
be tightly bandaged to the end-coils. These leads are connected to a pair of terminals on the motor terminal board, distinct from the
winding terminals.
In open machines the sensors are inserted in the winding about 1-2 cm from the point where the coils emerge from the slots at
the warm end of the machine. Having previously been dipped in resin, the sensors should be inserted in such a way, that they are
completely surrounded by winding wires and their distance from the rotor is as short as possible.
The stator is impregnated after the temperature sensors have been inserted and tested. The winding temperature must not exceed
175 °C for sensors with a rated operating temperature of 160 °C, or 220 °C for sensors rated 170 °C.
Mechanical stresses, especially tension, should be avoided at all costs when installing the sensors. Alignment of the end-coils should
therefore be carried out before insertion of the sensors. To protect the leads against mechanical damage they should also be covered
with an insulating hose, making quite sure that this does not cover the head of the sensor. If the length of the sensor leads has to be
increased, only use heat-resistant wire.
ATTENTION:
The voltage applied to the terminals of the temperature sensors must NOT exceed 2.5 V!
To prevent the application of an excessive voltage (e.g. test lamp) during installation, the enclosed triangular warning card
should be fastened to the terminals of the temperature sensor circuit.
English
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