Elmo DBP SERIES manual x VACmin VAC 0.9 x VACmax, Load inductance, AC power supply

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6.3 Load inductance

The total load inductance must be sufficient to keep the current ripple within the limits - 50% of the adjusted continuous current limit. The current

ripple (Ir) can be calculated by using the following equation:

0.5 x Vs
Ir = ----------	(A)
f x L
L - load inductance in mH.

Vs - Voltage of the DC supply in Volts. f - Frequency in KHz.

If motor inductance does not exceed this value, 3 chokes should be added (to each motor phase) summing together the required inductance

Lch = L - Lp

Lch - Choke inductance

Lp - Total inductance between two phases (in Y connection it is the sum of two phases).

6.4 AC power supply

AC power supply can be at any voltage in the range defined within the technical specifications. It must have the capability to deliver power to the amplifier (including peak power), without significant voltage drops. Any

voltage below the minimum or above the maximum will disable the amplifier.

The recommended AC voltage are:

1.2 x VAC(min) < VAC < 0.9 x VAC(max)

Note - Single phase connection:

When using a single phase supply, voltage drop due to loading is expected.

The magnitude of the voltage drop			depends on the load current, motor velocity,
stiffness of the power source and			total bus capacitance. It is recommended not
to use single phase connection for output current higher than 20A.
For 3U size amplifiers it is			recommended to add external capacitance as
follows:
For 135V	units	up to 1200 μF
For 270V	units	up to 600 μF

DBP - Rev 6/93