Inovance MDBUN-60-5T User Manual

Inovance MDBUN Series Braking Unit User Manual
Chapter 7 Selection of Braking Unit and Braking Resistor
7.1 Selection of Braking Unit
Select the braking unit by following two rules:
1. Select the braking unit of a proper input voltage class based on the input voltage class
of the drive.
2. Select the braking unit of proper power based on the braking power required by braking
of the drive.
Ensure that the power of the braking unit is larger than the braking power. If the braking
power is not known, estimate it according to the formula: Pb = P x Td x K.
In the formula:
Pb: braking power
P: motor power
K: mechanical energy conversion efficiency; generally, k = 0.7
Td: ration of braking torque to rated motor torque
Application
Elevator, hoist,
crane
Winding and
unwinding
equipment
Large-inertia
equipment that
requires quick
stop
Common-inertia
equipment
Td
100%
120%
120%
80%
7.2 Selection of Braking Resistor
7.2.1 Calculating the Resistance
During braking, almost all regenerative energy of the motor is consumed by the braking
resistor.
According to the formula U x U/R = Pb:
U refers to the braking voltage at system stable braking.
The value of U varies with different systems:
 220 VAC system: U = 380 V
 380 VAC system: U = 700 V
 480 VAC system: U = 800 V
If the calculated value of R is smaller than the minimum resistance under each voltage
class, multiple braking units need to be used.
7.2.2 Calculating Power of Braking Resistor
In theory, the power of the braking resistor is consistent with the braking power.
Considering de-rating use to 70%, you can calculate the power of the braking resistor
according to the formula 0.7 x Pr = Pb x ED.
 Pr: power of the braking resistor
 ED: braking frequency, that is, percentage of the regenerative process to the whole
working process

Inovance MDBUN-60-5T Specifications

General

Brand	Inovance
Model	MDBUN-60-5T
Category	Industrial Equipment
Language	English