Star-delta motor "Y/Δ"
A star-delta motor is installed in the compressor if the fields 1, 3 and 4 contain two columns with Δ or D in the first column and with Y in the second column and if the second column in the first field under Y 3Ph~ is empty.
The motor is first switched on in star configuration and then switched to delta configuration. This reduces the starting current. For further information, see online document AT-330.
A star-delta motor can also be used as a direct-on-line start motor at nominal voltage in delta operation. Direct-on-line start in star operation is also possible. However, this reduces the motor power to around a third. Designated special motors can be operated with √3 times nominal motor voltage.
- Only operate the motor under the conditions in power supply specified on the name plate.
- Design the main contactor Q02 and delta contactor Q03 for at least 60% of the max. operating current.
- Design the star contactor Q04 for at least 33% of the max. operating current.
- The star phase, i.e. the time from switch-on to switching from star to delta operation, must lie within this time:
1 .. 1.5 s for motors with maximum power consumption up to 50 kW
1 .. 2 s for motors with maximum power consumption between 50 and 200 kW
1.5 .. 2 s for motors with maximum power consumption above 200 kW
If the motor contactors are switched via the compressor module, it selects the appropriate time for each individual product. - Set the transition break from star to delta operation including the reaction times of the contactors to
40 .. 60 ms for motors with maximum power consumption up to 50 kW
60 .. 80 ms for motors with maximum power consumption between 50 and 200 kW
250 ms for motors with maximum power consumption above 200 kW - Strictly observe the phase connection arrangement on the motor!
- Incorrect arrangement results in a short-circuit or the compressor starts running in the opposite rotation direction!
The maximum power consumption be deduced from the type designation as the motor size. Motor size 10, for example, corresponds approximately to a maximum power consumption of 10 kW at 50 Hz and approximately to 12 kW at 60 Hz. Motor size, see explanation of the type designation, chapter 1.