Motors with temperature monitoring
The motors are equipped with PTC's as per DIN 44081. Take note of the temperature data and tripping time
t
A
on
the rating plate.
Connect the PTC to an approved tripping device with marking PTB 3.53-PTC/A or
II(2) G.
Please note!
The tripping device is not explosion-protected. For this reason install them outside the areas subject
to explosion hazards.
The marking confirms whether the electrical data on the interface between the temperature sensor circuit and the
tripping device have been fulfilled. The use of the tripping device with PTC temperature sensors as per DIN 44081 is
allowed for the thermal monitoring of explosion-protected electrical machinery.
Being the only overload protection as set forth in EN 60079-14, the temperature sensors herein described can be
used together with an approved tripping device only if the tripping time
t
A
is specified on the motor rating plate. (Re-
fer to Section 3, Operation & Repairs, page 17)
Motors with space heater
The rating data for the space heater are specified either on the rating plate or on a separate plate. Depending on the
model, there are two heating variants:
• by means of heater bands powered via terminals HE1-HE2
• by means of the stator winding by feeding AC voltage to terminals U1-V1.
Please note!
Make sure by means of the electric control that the motor
voltage and the heater voltage are not fed simultaneously.
Please note!
The heater is not explosion-protected. It must not be switched
on at motor temperatures below -20°C to heat the motor to at
least –20°C. On the contrary, its purpose is that of preventing
that the motor temperature falls below –20°C when idle.
Motors for operating on frequency converters
For operating on frequency converters, motors with temperature monitoring must be protected by PTC temperature
sensors rating data for this operating mode are specified either on the rating plate or on a separate plate. If the rele-
vant plate is missing, see the data provided in the manufacturer catalogue "Explosion-protected high and low voltage
AC motors in II 2 G EEx d(e) IIC(B) T4...T6“.
Check the drive's "electromagnetic compatibility" as per EMC directive no. 89/336/EEC when operating on frequency
converters.
Make sure when operating motors on frequency converters with a DC intermediate circuit that the admissible voltage
peak value of 1160 V is not exceeded by the periodically occurring commutation voltage peaks (threshold value for
terminals, clearances and creep distances).
If pulse width-modulated voltage source converters (pulse converter) are used for feeding power to the motors,
make sure that no high-frequency transients with high voltage peak values are generated. These may be generated
by the sharp switching edges of the voltage pulse especially along longer supply lines between the converter and
motor and shorten the life of the winding insulation. The normal design of the terminals and bushings for 750 V is
suitable for peak voltages of 1200 V. Higher voltage peaks require the application of bushings and terminals for
1100 V. The approved value for the periodic peak voltage amounts to 1600 V. If the periodic voltage peaks exceed
1600 V, high-voltage insulation systems must be applied.
In the case of a converter output non-galvanically separated from the mains and with current limitation, follow the
requirements of DIN EN 50178 and VDE 0160 (equipment of high voltage installations with electronic devices) on
the overload protection of the protective earth conductor.
In rating the protective device in the outer conductors, bear in mind that the protective earth conductor current can
be greater than the outer conductor current in fault condition. The protective earth conductor is to be dimensioned
according to this fault current.
