Keywords

Y2

deviceZ4

electricity

E29electrical machinery
Mitsubishi Electric Corporation

General-Purpose InverterFeatures
S The advanced optimal excitation control(*) has made possible large starting motor torque while maintaining
the energy-saving effects realized by the conventional optimal excitation control.
S Functions optimal for the use with fans and pumps, such as a function to maintain operation during
instantaneous power failure and PID control are included.
S Its capacity to control not only general-purpose motors, but also PM motors allows it to meet further needs forenergy saving.
S The pre-setting of the motor constants of the high-performance energy-saving motors(SF-PR series) and the premium high-efficiency IPM motors (MM-EFS series) allows
energy-saving operation of those motors only with the operating parameter setting.
S The off-line auto-tuning function allows operation of motors with the optimal operating
characteristics when motors of other manufacturers are used or wiring is long.
S “The self-power management” operated with an external DC 24 V power supply enables
reduction of standby power consumption.
S “Multiple ratings,” which allow selection of a rating in accordance with the load of fans andpumps, enable selection of an inverter with the optimal capacity for a motor to be used.
S The trace function can import data which occurred during operating troubles into a PC via
a USB memory device and the trouble can be analyzed.
S The reliability has improved by increasing the lifespans of parts which have fixed lifespans
and with the lifespan diagnosis function.
S The use of a 5-digit 12-segment LED display on the standard control panel enables aneasy-to-understand display.
* Achieved with the combination of the advanced magnetic flux vector control and the optimal excitation control

Basic Outline and Theory(1) Increased energy-saving due to optimal excitation control
The power consumption of loads with a squared relation between rotation speed and load, such as fansand pumps, is proportional to the rotational speed cubed. Therefore, controlling the rotation speed using
an inverter significantly reduces power consumption (Figure 1). With rotation speed control based on aninverter, V/F control, which carries out control so that the voltage and frequency ratio become constant,is common. However, optimal excitation control that controls voltage so that the efficiency of the motor ismaximized in order to further increase energy-saving effects was developed. For example, the efficiencyof a general-purpose motor (SF-PR four-pole, 15 kW) operated with the optimal excitation control isapprox. 15 % higher than the efficiency of the motor operated with the V/F control on the condition thatthe motor is operated at a load factor of 10 % (Figure 2). Since optimal excitation control is effective
during acceleration and deceleration, it is also effective for energy-saving for the purpose of repeating
starting and stopping. In addition, the newly developed advanced optimal excitation control realizes
generation of large torque by a motor at the start-up while maintaining the motor efficiency achieved withthe conventional optimal excitation control unchanged. It enables energy-saving motor operation withshort acceleration time and with the motor efficiency at the constant-speed operation maximized without
cumbersome adjustment of parameters (such as acceleration/deceleration time and torque boost).
(2) Further energy savings with the synchronous reluctance motor (RF-SR type motor)
The advanced high-efficiency technology reduces the generated loss by 20% in comparison with ourSF-PR type motor (IE3), and achieves the efficiency class rating of IE5.
The unit enables conservation of resources by not using any rare earth materials, and a reduction ofwaste power as this is a highly efficient energy-saving motor.
[Example of pump operation properties]
Dampercontrol

Motor efficiency

Power consumption (%)*

F-34

General-purposemotor (SF-PR)
Inverter-driven* The rated output ofthe motor is 100%.
Air volume (%)[Compared toconventionalcompany products]

Figure 1: An example of operating characteristics of a blower

Optimal excitation control
Improved energy efficiency
V/F control

Motor load factor[Compared toconventionalcompany products](When an inverter is operated at the frequency of 60 Hz with a 15 kW SF-PR 4P motor)

Figure 2: Energy saving with the optimal excitation control

Energy Savings Effects and Remarks
Power consumption and CO2
emissions can be reduced, whencompared with general IE1 andIE3 motors, by achieving theefficiency class rating of IE5.

F-34

Comparison of power consumption (MWh/year) and CO2 emissions(tons/year)
Powerconsumption(MWh/year）

CO2emissions(tons/year)

Approx.

11%

reduction
Calculation conditions

Approx.

 Load condition
5.5kW/3,000 min Operating time 17 hours/day for 335 days
 Inverter efficiency
96.2%
 CO2 conversion factor
0.555kg/kWh

6%

IE１motor

Synchronous reluctance motor
Type RF-SR

IE３ motor

Type RF-SR（IE５motor）

Inverter for driving synchronous reluctance motor
FR-A800-SYN
FR-F800-SYN

Actual Installations and Schedules
Japanese Domestic
Overseas

Contact:

reduction

Mitsubishi Electric Corporation
Tokyo Bldg., 2-7-3, Marunouchi, Chiyoda-ku, Tokyo 100-8310
Tel: +81-3-3218-2111
URL: http://www.mitsubishielectric.co.jp/