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3.4.3.3Supplying input power from a variac (variable transformer)

When AC power is supplied from a variac, the MicroFlex e100’s pre-charge circuit may not operate correctly. To ensure that the pre-charge circuitry operates correctly, increase the variac voltage to the desired level and then power cycle the 24VDC control circuit supply. This will restart the pre-charge circuit and allow it to operate correctly.

3.4.4 Power disconnect and protection devices

A power disconnect should be installed between the input power supply and the MicroFlex e100 for a fail-safe method to disconnect power. The MicroFlex e100 will remain in a powered condition until all input power is removed from the drive and the internal bus voltage has depleted.

The MicroFlex e100 must have a suitable input power protection device installed, preferably a fuse. Recommended circuit breakers are thermal magnetic devices (1 or 3 phase as required) with characteristics suitable for heavy inductive loads (C-type trip characteristic). Circuit breaker or fuses are not supplied - see section 3.4.5. For CE compliance, see Appendix C.

From

Circuit Breaker

supply

 

L

 

N

 

 

From

Fuse

 

supply

 

 

 

 

L

L

 

 

 

 

 

L

 

 

 

N

N

 

 

 

 

N

 

 

 

 

Figure 4 - Circuit breaker and fuse, single-phase

From

Circuit Breaker

supply

 

L1

 

From Fuses supply

L1L1

L2

L2L2

L3

L3L3

Circuit breaker or fuse are not supplied.

For CE Compliance, see Appendix C.

Figure 5 - Circuit breaker and fuse, three-phase

Note: Metal conduit or shielded cable should be used. Connect conduits so the use of a line reactor or RC device does not interrupt EMI/RFI shielding.

3.4.4.1Using 2 phases of a 3-phase supply

Power may be derived by connecting two phases of an appropriate three-phase supply (L1 and L2 for example). When supplying AC power in this way, the voltage between the two phases must not exceed the rated input voltage of the MicroFlex e100. A two pole breaker must be used to isolate both lines. Fuses must be fitted in both lines.

3-14 Basic Installation

MN1942

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Image 28
Baldor E100 manual Power disconnect and protection devices, Supplying input power from a variac variable transformer