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Care must be taken to ensure that the insulation distances in air and on the surfaces between the
conductors are maintained, as established by the standards.
All screws utilized to seal the motor and the terminal board must be fully tightened.
Replacement of gaskets and cable entry parts shall be executed using components that are identical
to the components supplied by the manufacturer to ensure the protection degree is maintained. The
surfaces of flameproof joints must not be machined and sealing gaskets different from those supplied
by the manufacturer must not be inserted. These surfaces must be maintained in a clean condition. A
thin layer of non-hardening grease must be used against corrosion and to prevent water from
entering. This grease layer must be renewed at every disassembly.
6. CONNECTING TO THE POWER SUPPLY NETWORK AND SAFETY/PROTECTION MEASURES
Insulation Check & Replacement of Grease / Bearings
When the motor is first commissioned and especially after extended storage, the insulation resistance
of the winding is to be measured to earth and between phases. The check must take place using the
rated voltage, but at least 500 V.
During and immediately after the measurements dangerous voltages are present at the
terminals. Therefore never touch the terminals and follow the operating instructions of
the insulation resistance meter closely!
Depending on the rated voltage UN, the following minimum values must be maintained with a winding
temperature of 25 °C:
Rated Power PN in kW Insulation Resistance referred to Rated Voltage in k
/V
1 < PN <= 10
6,3
10 < PN <= 100
4
100 < PN
2,5
If the minimum values are lower, the winding must be dried properly until the insulation resistance
corresponds to the required value.
When the motor is commissioned after a prolonged period of storage inspect the bearing grease
visually and replace it if hardening and other irregularities occur. If the motors are to be commissioned
by the manufacturer after more than three years following their delivery then the bearing grease must
always be replaced. With motors fitted with covered or sealed bearings the bearings must always be
replaced with new bearings of the same type after a storage period of four years.
Motor connection
The connection should be carried out by experts in accordance with
the applicable safety requirements- should apply the relevant
national regulations. Obey the nameplate!
Before connecting
the motor to power supply special attention must be given to the following:
that the motor data on the nameplate corresponds to the power supply voltage and frequency
that the terminals are connected according to appropriate connection diagram labeled inside the
motor terminal box, or according to the nameplate data and the power supply itself (in case if
motor starting via the Y/D switch is requested, the bridges from terminal plate must be removed!)
that the protection of live parts is maintained according to local safety regulations. The earthing
lead must be connected to a specially marked place inside the terminal box and the motor must
be earthed also with a bolt situated outside on the frame. Earthing lead cross-section area must
be greater than or equal to those of phase lead. Depending on the cross-section of the line
conductor, the earthing conductor cross-section must be:
LINE CONDUCTOR SECTION
EARTH CONDUCTOR SECTION
≤
4 mm
2
≥
4 mm
2
4 mm
2
- 25 mm
2
Same section or greater
25 mm
2
- 50 mm
2
≥
50 mm
2
≥
50 mm
2
≥
50% of the section
- all valid safety measures must be regarded acc. to actual protection system against the
electric current shock
that terminal box interior is free from dirt, connecting material particles or similar
