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.