1、 Micro motor dynamometers generally use high-precision hysteresis dynamometers, which are composed of a toothed pole stator, a hollow hysteresis cup rotor, an excitation coil, a bracket, a base plate, etc. When the internal coil of the hysteresis dynamometer passes current, magnetic lines are generated and a magnetic circuit is formed to generate torque. Changing the excitation current can change the load torque.
2、 Hysteresis dynamometer is suitable for testing low to medium power motors. Hysteresis dynamometer does not rely on speed to generate torque, so it can perform full range testing from no-load to locked rotor. The cooling methods of hysteresis dynamometer can be divided according to different models: convection air cooling, compressed air cooling, blower cooling, water cooling, and air conditioning cooling. Different models of dynamometer can be configured according to different motor parameters, and their accuracy can reach ± 0.25% - ± 0.5% of full range.

High precision hysteresis dynamometer parameter table
model	Rated torque	rated power		maximum speed
HD	N.m	Rated power within 5 minutes	Continuous rated power	rpm
HD-301	0.03	80	20	30000
HD-501	0.05	80	20	30000
HD-102	0.1	200	80	25000
HD-202	0.2	200	80	25000
HD-302	0.3	4000	120	25000
HD-502	0.5	400	120	25000
HD-103	1.0	800	375	25000
HD-203	2.0	1000	500	25000
HD-303	3.0	1300	800	25000
HD-503	5.0	1500	1200	25000
HD-603	6.0	2500	1500	25000
HD-144	14.0	2800	1800	12000
HD-284	28.0	5000	2800	10000