SYNCHRONOUS RELUCTANCE MOTOR (SynRM)

SYNCHRONOUS RELUCTANCE MOTOR (SynRM)

The SynRM combines the stator from conventional induction motors with an innovative rotor design, creating a highly efficiency, speed-adjustable motor, capable of achieving an IE5 efficiency rating, allowing up to 20% energy savings compared to an equivalent induction machine. Its performance is comparable to permanent magnet motors, without the environmental and financial cost of rare earth metals. The controller for the SynRM is essential for its operation, ensuring the correct energisation of the windings to produce the required motion

SynRM Operating Principle

The stator of the synchronous reluctance motor is similar to that of the traditional induction motor; however, its rotor is made only of laminated silicon steel sheets, with no windings. The silicon steel sheets are designed with hollow air gaps as magnetic field barriers. The direction of these barriers is called the quadrature (q) axis, while the direction of the path with the continuous silicon steel sheet is called the direct (d) axis.

The stator of the SynRM contains windings which are energised from a three-phase supply which results in a rotating magnetic field. The diagram shows the flow of flux from three pairs of windings, the others are omitted for clarity. When the voltage of the first phase is a maximum, the rotor aligns itself so the reluctance is at a minimum (A), the reluctance paths for the other phases are much greater. As the second phase voltage reaches a maximum, the first phase voltage has reduced and the rotor re-aligns with the second phase, as this now presents the path of least reluctance. This is then repeated with the third phase and so on. As the field rotates, the rotor follows it synchronously.

A SynRM is a synchronous speed-regulating motor in which the rotor operates synchronously with an applied sinusoidal magnetic field. It needs to be powered by a dedicated KSYC series controller to control the speed and torque. It provides:

  • high-speed control precision, with a wide range of speed adjustment and long-term operation at low speeds.
  • high-torque control precision, realising servo-control performance, with four-quadrant operation and regenerative braking.
  • communication interfaces including CAN bus, RS232 and RS485. It has a multi-channel switch and analogue input and output interfaces, which facilitate remote monitoring and interfacing with an external device such as a PLC or a computer.
Why should the motor speed be adjusted?

The load applied to the motor is never completely constant and, usually, the motor does not need to run at its full speed or power. By adjusting the speed and torque to match the operation of the motor to the load, between 25% to 30% of the electric energy can be saved. For example, valves are often used to control the flow rate of water in water pumps. This is equivalent to slowing a car by applying the brakes without releasing the accelerator, which is a waste of energy. By adjusting the speed of the motor in real time, the controller removes the need for valves, gears or brakes to control the speed of the equipment driven by the motor, and there will be no waste of electrical energy which would result from mechanical speed regulation.

Motor Selection Chart

SynRM type Rated Power (kW) Rated Torque (N·m) Rated Current (A) Rated Efficiency (%) Speed Range (r/min) Maximum
Overload
Torque
Weight (kg) Rotational Inertia       (kg m2 Insulation Grade

 750r/min

KSYM1-160M1-8 4 51 9.5 85.45 5-1000 1.5 120 0.082 H
KSYM1-160M2-8 5.5 70 12.4 86.78 5-1000 1.5 138 0.093 H
KSYM1-160L-8 7.5 96 15.7 87.89 5-1000 1.5 180 0.122 H
KSYM1-180L-8 11 140 24.4 91.15 5-1000 1.5 202 0.142 H
KSYM1-200L-8 15 191 36.0 90.01 5-1000 1.5 276 0.250 H
KSYM1-225S-8 18.5 236 43.0 90.57 5-1000 1.5 330 0.375 H
KSYM1-225M-8 22 280 50.5 91.02 5-1000 1.5 363 0.501 H
KSYM1-250M-8 30 382 72.0 91.7 5-1000 1.5 435 0.687 H
KSYM1-280S-8 37 471 82.0 92.15 5-1000 1.5 540 1.212 H
KSYM1-280M-8 45 573 101.0 92.48 5-1000 1.5 650 1.429 H
KSYM1-315S-8 55 700 105.0 92.82 5-1000 1.5 1012 1.640 H
KSYM1-315M-8 75 955 145.0 93.39 5-1000 1.5 1076 1.874 H
KSYM1-315L1-8 90 1146 180.0 93.61 5-1000 1.5 1138 2.134 H
KSYM1-315L2-8 110 1401 208.0 93.86 5-1000 1.5 1220 2.350 H

1000r/min

KSYM1-160M-6 7.5 72 17.0 90.12 5-1500 1.5 160 0.070 H
KSYM1-160L-6 11 105 24.9 91.25 5-1500 1.5 177 0.086 H
KSYM1-180L-6 15 143 33.1 91.92 5-1500 1.5 242 0.242 H
KSYM1-200L1-6 18.5 177 41.5 92.48 5-1500 1.5 304 0.287 H
KSYM1-200L2-6 22 210 47.5 92.82 5-1500 1.5 328 0.310 H
KSYM1-225M-6 30 286 68.4 93.39 5-1500 1.5 391 0.499 H
KSYM1-250M-6 37 353 81.8 93.73 5-1500 1.5 428 0.575 H
KSYM1-280S-6 45 430 100.0 94.07 5-1500 1.5 639 1.012 H
KSYM1-280M-6 55 525 121.5 94.41 5-1500 1.5 690 1.029 H
KSYM1-315S-6 75 716 162.2 94.75 5-1500 1.5 873 1.640 H
KSYM1-315M-6 90 859 202.0 94.97 5-1500 1.5 925 1.874 H
KSYM1-315L1-6 110 1050 244.5 95.00 5-1500 1.5 965 2.080 H
KSYM1-315L2-6 132 1261 280.2 95.10 5-1500 1.5 1116 2.450 H

1500r/min

KSYM1-132S-4 5.5 35 12.0 90.8 5-2000 1.5 68 0.022 H
KSYM1-132M-4 7.5 48 16.0 91.58 5-2000 1.5 81 0.026 H
KSYM1-160M-4 11 70 23.3 92.37 5-2000 1.5 126 0.042 H
KSYM1-160L-4 15 96 31.3 93.05 5-2000 1.5 147 0.051 H
KSYM1-180M-4 18.5 118 42.0 93.39 5-2000 1.5 187 0.080 H
KSYM1-180L-4 22 140 49.7 93.73 5-2000 1.5 204 0.183 H
KSYM1-200L-4 30 191 71.5 94.18 5-2000 1.5 274 0.287 H
KSYM1-225S-4 37 236 89.3 94.52 5-2000 1.5 332 0.425 H
KSYM1-225M-4 45 287 105.9 94.75 5-2000 1.5 359 0.575 H
KSYM1-250M-4 55 350 127.0 95.09 5-2000 1.5 479 0.632 H
KSYM1-280S-4 75 477 177.2 95.43 5-2000 1.5 582 1.000 H
KSYM1-280M-4 90 573 211.0 95.54 5-2000 1.5 642 1.211 H
KSYM1-315S-4 110 700 235.0 95.62 5-2000 1.5 994 1.643 H
KSYM1-315M-4 132 840 289.9 95.74 5-2000 1.5 1097 1.870 H
KSYM1-315L1-4 160 1019 350.2 95.89 5-2000 1.5 1118 2.041 H
KSYM1-315L2-4 200 1273 428.9 95.91 5-2000 1.5 1169 2.452 H
KSYM1-180M-4 18.5 118 42.0 93.39 5-2000 1.5 187 0.080 H
KSYM1-180L-4 22 140 49.7 93.73 5-2000 1.5 204 0.183 H
KSYM1-200L-4 30 191 71.5 94.18 5-2000 1.5 274 0.287 H
KSYM1-225S-4 37 236 89.3 94.52 5-2000 1.5 332 0.425 H
KSYM1-225M-4 45 287 105.9 94.75 5-2000 1.5 359 0.575 H
KSYM1-250M-4 55 350 127.0 95.09 5-2000 1.5 479 0.632 H
KSYM1-280S-4 75 477 177.2 95.43 5-2000 1.5 582 1.000 H
KSYM1-280M-4 90 573 211.0 95.54 5-2000 1.5 642 1.211 H
KSYM1-315S-4 110 700 235.0 95.62 5-2000 1.5 994 1.643 H
KSYM1-315M-4 132 840 289.9 95.74 5-2000 1.5 1097 1.870 H
KSYM1-315L1-4 160 1019 350.2 95.89 5-2000 1.5 1118 2.041 H
KSYM1-315L2-4 200 1273 428.9 95.91 5-2000 1.5 1169 2.452 H

3000r/min

KSYM1-132S1-2 5.5 17 12.5 89.68 5-3600 1.5 41 0.015 H
KSYM1-132S2-2 7.5 24 17.0 90.57 5-3600 1.5 50 0.018 H
KSYM1-160M1-2 11 35 25.8 91.58 5-3600 1.5 130 0.058 H
KSYM1-160M2-2 15 48 34.6 92.37 5-3600 1.5 142 0.063 H
KSYM1-160L-2 18.5 59 44.0 92.82 5-3600 1.5 149 0.066 H
KSYM1-180M-2 22 70 51.0 93.16 5-3600 1.5 160 0.071 H
KSYM1-200L1-2 30 95 68.9 93.73 5-3600 1.5 260 0.203 H
KSYM1-200L2-2 37 118 35.1 94.07 5-3600 1.5 271 0.225 H
KSYM1-225M-2 45 143 102.0 94.29 5-3600 1.5 285 0.242 H
KSYM1-250M-2 55 175 125.5 94.63 5-3600 1.5 425 0.610 H
KSYM1-280S-2 75 239 158.8 94.97 5-3600 1.5 550 0.975 H
KSYM1-280M-2 90 286 198.0 95.2 5-3600 1.5 592 1.120 H

Motor Dimensions

Model Number No. of poles* Dimension (mm)
H A B C D E F×GD G K AB AC AD HD L
132S 2.4 132 216 140 59 38 80 10×8 33 12 280 275 210 315 545
132M 4 178 585
160M 2.4.6.8 160 254 210 108 42 110 12×8 37 15 320 330 255 420 675
160L 254 720
180M 180 279 241 121 48 14×9 42.5 355 380 280 455 730
180L 279 770
200L 200 318 305 133 55 16×10 49 19 395 420 305 505 840
225S 4.8 225 356 286 149 60 140 18×11 53 435 470 335 560 875
225M 2 311 55 110 16×10 49 890
4.6.8 60 140 18×11 53 900
250M 2 250 406 349 168 24 490 510 370 615 1000
4.6.8 65 58
280S 2.4.6.8 280 457 368 190 75 20×12 67.5 550 580 410 680 1040
280M 419 1090
315S 4.6.8 315 508 406 216 80 170 22×14 71 28 635 645 530 845 1270
315M 457 1385
315L 508

* The pole number indicates the speed of the motor: 2 pole is 3000rpm; 4 pole is 1500rpm; 6 pole is 1000rpm and 8 pole is 750rpm.

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