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1. OVERVIEW
1.3
Electrical Installation - General Notes
1.3.1
Operation with Unearthed (IT) Supplies
The MICROMASTER will operate from unearthed supplies and will continue to operate if an input phase is
shorted to earth. If an output phase is shorted to earth, the MICROMASTER will trip and indicate F002.
1.3.2
Operation with Residual Current Device (RCD)
The MICROMASTER inverters will operate without nuisance tripping with an RCD (also called ELCBs or
RCCBs) fitted to the input providing:
• A type B RCD is used.
• The trip limit of the RCD is 300mA.
• The neutral of the supply is earthed.
• Only one inverter is supplied from each RCD.
• The output cables are less than 50m (screened) or 100m (unscreened).
1.3.3
Installation after a Period of Storage
It is necessary to reform the capacitors in the inverter if the unit has been stored for a prolonged period.
•
Period of storage 1 year old or less:
No reforming is required.
•
1 - 2 years old:
Apply power to the inverter one hour before giving the run command. (Preparation time 1 Hour)
• 2 - 3 years old:
Use a variable AC supply. Apply 25% of input voltage for 30 minutes. Increase volts to 50% for a further
30 minutes. Increase volts to 75% for further 30 minutes. Increase volts to 100% for a further 30 minutes.
Now ready for run signal. (Preparation Time 2 hours)
•
3 years and over:
As with 2 - 3 years, but the steps should be 2 hours. (Preparation Time 8 Hours)
1.3.4
Operation with Long Cables
Motor cable lengths vary depending on type of cable, power rating and voltage rating - and in some cases can
be as long as 200m without the need for additional chokes. Refer to DA64 catalogue for further details.
In any case, all inverters will operate at full specification with cable lengths up to 25m for screened cable or
50m for unscreened cables.
© Siemens plc 1999
9
English
G85139-H1750-U049-C1
19/08/99
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