Frequently Asked Questions - Omron 3G3MX2 User Manual

Frequently Asked Questions

1-4 Frequently Asked Questions
18
Q. What is the main advantage in using an inverter to drive a motor, com-
pared to alternative solutions?
A. An inverter can vary the motor speed with very little loss of efficiency,
unlike mechanical or hydraulic speed control solutions. The resulting ener-
gy savings usually pays for the inverter in a relatively short time.
Q. The term "inverter" is a little confusing, since we also use "drive" and
"amplifier" to describe the electronic unit that controls a motor. What does
"inverter" mean?
A. The term inverter, drive, and amplifier are used somewhat interchange-
ably in industry. Nowadays, the term drive, variable-frequency drive, vari-
able-speed drive, and inverter are generally used to describe electronic,
microprocessor-based motor speed controllers. In the past, variable-
speed drive also referred to various mechanical means to vary speed. Am-
plifier is a term almost exclusively used to describe drives for servo or step-
per motors.
Q. Although the MX2 inverter is a variable speed drive, can I use it in a fixed-
speed application?
A. Yes, sometimes an inverter can be used simply as a "soft-start" device,
providing controlled acceleration and deceleration to a fixed speed. Other
functions of the MX2 may be useful in such applications, as well. However,
using a variable speed drive can benefit many types of industrial and com-
mercial motor applications, by providing controlled acceleration and decel-
eration, high torque at low speeds, and energy savings over alternative
solutions.
Q. Can I use an inverter and AC induction motor in a positioning application?
A. That depends on the required precision, and the slowest speed the mo-
tor must turn and still deliver torque. The MX2 inverter will deliver full
torque while turning the motor at 6Hz (180RPM). DO NOT use an inverter
if you need the motor to stop and hold the load position without the aid of
a mechanical brake (use a servo or stepper motion control system).
Q. Can the inverter be controlled and monitored via a network?
A. Yes. MX2 inverters have built-in ModBus communications. See Appen-
dix B for more information on network communications.
Q. Why does the manual or other documentation use terminology such as
"200 V class" instead of naming the actual voltage, such as "230 VAC"
A. A specific inverter model is set at the factory to work across a voltage
range particular to the destination country for that model. The model spec-
ifications are on the label on the side of the inverter. A European 200V
class inverter ("EU" marking) has different parameter settings than a USA
200 V class.
Q. Why doesn't the motor have a neutral connection as a return to the
inverter?
A. The motor theoretically represents a "balanced Y" load if all three stator
windings have the same impedance. The Y connection allows each of the
three wires to alternatively serve as input or return on alternate half-cycle.
Section 1-4