Application Notes - YASKAWA A1000 Technical Manual

 Application Notes

Selection
Installing a Reactor
An AC or DC reactor can be used for the following:
• to suppress harmonic current.
• to smooth peak current that results from capacitor switching.
• when the power supply is above 600 kVA.
• when the drive is running from a power supply system with thyristor converters.
Note: A DC reactor is built in to the drive models 2A0110 to 2A0415 and 4A0058 to 4A1200.
Figure i.1
Drive Capacity
For specialized motors, make sure that the motor rated current is less than rated output current for the drive. When
running more than one motor in parallel from a single drive, the capacity of the drive should be larger than 1.1 times of
the total motor rated current.
Starting Torque
The overload rating for the drive determines the starting and accelerating characteristics of the motor. Expect lower
torque than when running from line power. To get more starting torque, use a larger drive or increase both the motor and
drive capacity.
Emergency Stop
When the drive faults out, the output is shut off. This, however, does not stop the motor immediately. Some type of
mechanical brake may be needed if it is necessary to halt the motor faster than the Fast Stop function is able to.
Options
The B1, B2, -, +1, +2, and +3 terminals are used to connect optional devices. Connect only A1000-compatible devices.
Repetitive Starting/Stopping
Cranes (hoists), elevators, punching presses, and other such applications with frequent starts and stops often exceed
150% of their rated current values. Heat stress generated from repetitive high current can shorten the life span of the
IGBTs. The expected lifesaving for the IGBTs is about 8 million start and stop cycles with a 2 kHz carrier frequency and
a 150% peak current.
YASKAWA recommends lowering the carrier frequency, particularly when audible noise is not a concern. The user can
also choose to reduce the load, increase the acceleration and deceleration times, or switch to a larger drive. This will help
keep peak current levels under 150%. Be sure to check the peak current levels when starting and stopping repeatedly
during the initial test run, and make adjustments accordingly.
For crane-type applications using an inching function in which the motor is quickly started and stopped, YASKAWA
recommends the following to ensure motor torque levels:
• Select a large enough drive so that peak current levels remain below 150% of the drive rated current.
• The drive should be one frame size larger than the motor.
YASKAWA ELECTRIC SIEP C710616 27G YASKAWA AC Drive A1000 Technical Manual
4000
Power supply harmonics
reactor required
Power Supply
Capacity (kVA)
600
0
Figure i.1 Installing a Reactor
Reactor
unnecessary
60 400
Drive Capacity (kVA)
i.2 General Safety
21