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connected to the terminal board of the actuator. For other electric motors, the thermal cut-out is connected by two
separate outlet wires to the terminal board of the electric motor and the motor is controlled by means of another device
(contactor, relay, etc.).
Insulation resistance
Before putting the actuator into operation or restarting it after a longer idle time, it is necessary to check that
insulation conditions have not been worsened and that there is no danger of the winding damage or electric shock.
Insulation conditions should also be checked during inspections in compliance with provisions of ČSN 34 3205 and
standards valid for non-explosive electric installations. Insulation resistance of electric control circuits against the frame
and against each other should be min. 20 Mohm. Insulation resistance of the electric motor should be min 1.9 Mohm.
Insulation resistance of the current transducer is 20 Mohm at 50 V DC.
The actuators with a lower insulation resistance must not be put into operation. The cause can lie in a damaged
winding or excess humidity. Damp motors with insulation resistance lower than the stated value must be carefully dried
before being put into operation. By drying the winding, moisture is removed from the insulation and insulation resistance
is thus increased to the prescribed value. Drying can be carried out in different ways. Drying directives are given by the
standard ČSN 35 0010 or local recommended methods can be applied.
Supply line and wiring
Cable entries into actuators flameproof enclosure are equipped with the followings threaded holes:
a)
Actuator – has 2 or 3 threaded entries M20x1,5 nebo M25x1,5
(see dimensional drawing of actuators)
b)
Local control – has 2 threaded entries M20x1,5.
Threaded holes for cable entries are marked M20x1,5 or M25x1,5 in accordance with article 13 of ČSN EN 60079-1.
These entries are sealed by appropriate plugs.
The customer is obliged to establish electrical connection for direct entry to the flameproof enclosure, that
corresponds to the requirements of ČSN EN 60079-14 and the protective enclosure is at least IP67.
At the customer's request, the manufacturer can supply motors with cable bushing system that meets the requirements
of ČSN EN 60079-14 Article 10.4.2.d for direct entry into flameproof enclosure of group IIC. For entry into actuators
flameproof enclosure are used Peppers glands (type CR-U) or HAWKE glands (type ICG 623) according to following
table.
Cable diameter
Gland
Threaded entry
CR-U/25
M25x1,5
11,7 – 20,0 mm
ICG 623/B
M25x1,5
13,0 – 20,2 mm
CR-U/20
M20x1,5
9,5 – 14,0 mm
ICG 623/A
M20x1,5
11,0 – 14,3 mm
