AMCI SV160E2, User Manual, Page: 23 / 120

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SV160E2 User Manual
SV160E2 S
PECIFICATIONS
23
Regeneration (Back EMF) Effects
All motors generate electrical energy when the mechanical speed of the rotor is greater than the speed of the
rotating magnetic fields set by the drive. This is known as regeneration, or back EMF. Designers of systems
with a large mass moment of inertia or high deceleration rates must take regeneration effects into account
when selecting power supply components.
The first line of defense against regenerative events is an appropriately sized power supply. The additional
capacitance typically found in a larger supplies can be used to absorb the regenerative energy. If your applica-
tion has high deceleration rates, then a supply that can deliver 175% of peak motor power should be used.
The second line of defense is a braking resistor, also known as a regeneration resistor. Braking resistors, and
their control circuitry, are built into AMCI AC powered drives. They are not included in the SV products
because of the limited ability to dissipate the heat generated by the resistor. An external braking resistor and
control circuitry can be added to the system. The power switches in the SV160E2 units can conduct a maxi-
mum of 10 amps, so the sum of the motor current and braking resistor circuit currents must be below this
value.
The Braking Resistor Calculations section, which starts on page 73, lists the steps needed to choose a prop-
erly sized braking resistor for your application.
Regeneration events can raise the Vdc supply voltage to an unexpected value. Compo-
nents not rated for this voltage may be damaged.
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Only use power supplies that will not be damaged by regeneration events.
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Use a braking resistor if necessary.