Delta VFD-B Series User Manual

Appendix C How to Select the Right AC Motor Drive|VFD-B-P Series
Revision April 2009, SW V1.00 C-5
4. If the stall prevention function is activated, the accel./decel. time is automatically extended
to a length that the AC Motor Drive can handle. If the motor needs to decelerate within a
certain time with high load inertia that can’t be handled by the AC Motor Drive in the
required time, either use an external brake resistor and/or brake unit, depending on the
model, (to shorten deceleration time only) or increase the capacity for both the motor and
the AC Motor Drive.
C.3 How to Choose a Suitable Motor
Standard motor
When using the AC Motor Drive to operate a standard 3-phase induction motor, take the
following precautions:
1. The energy loss is greater than for an inverter duty motor.
2. Avoid running motor at low speed for a long time. Under this condition, the motor
temperature may rise above the motor rating due to limited airflow produced by the
motor’s fan. Consider external forced motor cooling.
3. When the standard motor operates at low speed for long time, the output load must be
decreased.
4. The load tolerance of a standard motor is as follows:
3 6 20 60
100
82
70
60
50
0
60%
40%
25%
torque(%)
continuous
Frequency (Hz)
Load duty-cycle
5. If 100% continuous torque is required at low speed, it may be necessary to use a special
inverter duty motor.

Delta VFD-B Series Specifications

General

Series	VFD-B
Cooling Method	Fan cooling
Overload Capacity	150% for 60 seconds
Braking Unit	Built-in
Control Mode	V/F control, Sensorless Vector Control
Communication	RS-485
Protection Features	Overvoltage, Undervoltage, Overcurrent, Overload, Overtemperature, Short Circuit
Operating Temperature	-10°C to +50°C
Storage Temperature	-20°C to +60°C
Humidity	90% RH (non-condensing)
Altitude	1000m (Derating required above 1000m)