Siemens SIMOTICS HT Series, Operating Instructions & Installation Instructions

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Damage caused by the short-circuit current
When the permanent magnet rotor is a driven, a voltage ("rotor voltage") is induced in the
stator winding, that can be measured at the motor terminals. If a cable or converter short-circuit
simultaneously occurs, then a short-circuit current is driven by the induced rotor voltage. This
can result in material damage.
● Use cables that are short-circuit proof.
● Alternatively, use a circuit breaker close to the motor to protect the cable against a short
circuit.
Damage due to overheating
If the cooling water supply fails or if the motor is operated for a short time without water cooling,
the motor will overheat. This can result in material damage, or even destroy the machine
completely.
● Never operate the motor without the cooling water supply switched on.
● Monitor the permissible water intake temperatures.
Risk of burns from hot steam
If the cooling water supply fails, the motor will overheat. If cooling water enters the hot machine,
hot steam will suddenly be generated, which escapes under high pressure. The cooling water
system can burst. This can result in death, serious injury or material damage.
● Do not connect the cooling water supply until the machine has cooled down.
8.2 Switching on the machine
1. If at all possible, run the machine without load and check that it is running smoothly.
2. If it runs perfectly, connect a load.
NOTICE
Thermal overload of motors connected directly to the line supply
In addition to the load torque, the ramp-up (accelerating) time is essentially influenced by
the moment of inertia to be accelerated. While ramping up when connected to the line
supply, the inrush (starting) current is a multiple of the rated current. This can result in
thermal overload. This can damage the motor.
As a consequence, when ramping up, observe the following:
● Monitor the ramp-up time and number of consecutive starts.
● Comply with the limit values and/or ramp-up conditions specified in the catalog or the
order documentation.
3. If this is possible using the available measuring equipment, check the bearing and stator
winding temperatures.
Operation
8.2 Switching on the machine
SIMOTICS HT Series HT-direct 1FW4...1......A
Operating Instructions 11/2018
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