NVF5 Series User Manual Chapter 3 Installation and Wiring
Supply
Catalog No.
Power
Brake Unit
Value
Power
W
AC
230V
0.4
Optional
(embedded)
-- --
0.75 150 80
1.5 100 150
2.2 75 250
AC
380V~440V
Standard
(embedded)
Note： The usage and working conditions needs to be considered when selecting brake
resistor. The following is a description of brake resistor selection：
（1）Brake Resistor Calculation
When the output current equals half the rated current of the motor, the same braking
torque can be obtained as the rated torque of the motor，so the rough calculation of brake
resistor is：
=
，
is brake voltage，
is motor rated current，to ensure that the
inverter is not damaged, the minimum value of the brake resistor is
when the
current flowing through the brake resistor is motor rated current. When selecting the
resistance of the brake resistor, it must not be less than the below value.
=
According to the above description, the selection range of brake resistor is：
<
（2）Brake Resistor Power Calculation
The power of brake resistor：
=
The brake resistor power is mainly determined by the brake utilization rate ED%.
Because the braking time of the system is relatively short, the temperature rise of the
braking resistor is not enough to achieve a stable temperature rise.So the principle for
determining the brake resistor capacity is to minimize the brake resistor capacity if the
temperature rise of the brake resistor does not exceed its allowable value (i.e. the rated
temperature rise)，The rough algorithm is as follows：
= % =
%，
= 1
|
|
is brake resistor derating coefficient（Normally select
）。
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