CDE360 Vector Control AC Drive Chapter 2 Product Information
Remarks:
1) Voltage and power classes is the only consideration in brake resistance selection.
2) “ × ” means there needs several groups of braking units and resistance to be used in parallel.
3) If external brake unit is needed, please refer to the related user manual of brake unit.
The data in the above table is only for reference. The user can select different resistance and power
of the resistor based on actual needs (here, the resistance should not be less than the recommended
value in the table, and the power of the resistor can be higher than the recommended value in the
table). The brake resistance can be determined by the regenerative power of the motor in the actual
system and is also related to the inertia of the system,deceleration time and potential energy load.
The user can select the brake resistance based on the actual needs.
For systems with high inertia,rapid deceleration time and frequent braking, the brake resistor with
high power and small resistance should be selected.
Selection of the Resistance
The consumption of the regenerative energy of the motor is almost entirely on the braking
resistance.
According to the formula U×U/R=Pb, the user can calculate the resistance of the braking resistor.
In the formula, U------braking voltage of the system during the constant status (different systems
have different brake voltage. As for 380VAC system, usually the braking voltage is 700V).
Pb------braking power.
Selection of the Power
In theory, the power of the braking resistor should be consistent with the braking power. But
considering actual conditions, the derating is 70 percent.
The formula is 0.7×Pr=Pb×D.
Pr refers to the power of the braking resistor.
D refers to the braking frequency (percentage of the regenerative process to the whole process),the
selection of the braking frequency can be as follows based on the experience:
Elevator load is 20% to 30%; Winding load is 20% to 30%
Centrifuge load is 50% to 60%; Intermittent braking load is 5%;
Ordinary load is 10% (10% is enough for the ordinary load).
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