Direct drive type

Special permanent magnet direct drive motor for belt conveyor

The special low-speed high-power permanent magnet drive system for belt conveyor is a high-efficiency and energy-saving direct-drive electric drive system, which directly drives the load equipment. Different from the traditional asynchronous motor, selection of the system depends on the actual equipment speed range and the equipment load torque. The specific selection rules are as follows:

Determine the motor speed range according to the belt speed and roller outer diameter of the belt conveyor, to select the motor drive system whose speed range is not less than and closest to the actual demand. The standard rated speed is 0~60r/min, 0~75r/min, 0~90r/min, and other speed range can be adjusted and customized according to the actual requirements of customers.

Confirm the torque required by the belt conveyor first to select the appropriate permanent magnet drive system. The actual torque of the equipment can also be calculated according to the parameters of traditional asynchronous motor and the speed ratio of reducer.

Determine the rated voltage of the motor. The common voltage of the motor under the torque of 30000N.m is 380V, 660V, 1140V. The motor voltage above the torque of 30000N.m is 1140V, 3300V, 6kV, 10kV. Other voltage levels can be customized according to customer needs.

Motor cooling mode includes natural cooling, forced air cooling and water cooling, which can be selected according to customers’ actual needs.

The motors can be designed and manufactured according to the technical parameters provided by users.

If the motor parameters are clear, it can be selected according to this Catalog Parameter List.


Traditional driving of belt conveyor

Traditional belt conveyor structure: asynchronous motor + reducer, hydraulic coupler to drive roller.


But the asynchronous motor drive has the following problems:

Low power factor and high energy consumption;

Directly driven by electric power, large starting current;

The volume of power supply transformer is increased, and the running is not stable when starting, which causes a certain impact on the belt;

Without special control equipment, with no monitoring data in real time, so the centralized control effect is poor.

The reducer in the front has large mechanical loss, low transmission rate, low operating efficiency and large energy consumption.

The reducer is large, with complex structure, high difficulty in installation, high failure rate and heavy work load of maintenance;

Frequent lubricating oil change;

More investment in installation and maintenance costs, low performance cost ratio.


Special low speed big power permanent magnet drive system for belt conveyor

The special drive system is customized according to the operation characteristics of belt conveyor. With advanced design concept and production processing technology and equipment, the low-speed high-power permanent magnet motor drive system has formed 315, 355, 400, 500, 560 five seat Nos, with torque ranges 3000 N · m ~ 100000 N · m, a series products of more than 120 specifications, widely applied in the port, mining machinery and other fields.

The products adopt the latest electromagnetic program and structural design, with characteristics of energy-saving, efficient, small size, light weight, high torque density, anti-demagnetization, easy installation, maintenance-free, high cost-performance ratio. The products are suitable for a variety of low-speed high-power belt transmission equipment.




Torque range


Seat No.



380VAC, 660VAC, 1140VAC, 3300VAC或6K,10K

Speed range

0~60, 75, 90rpm/min, or customized as per customers’ requirement

Cooling type

natural cooling, water cooling


horizontal installed or customized as per customers’ requirement

Protection grade

IP54 (higher grades can be customized)

Shaft standard

circular shaft with keyway, hollow shaft with key, hollow shaft with internal spline


Performance, cost, parameter comparisons



low speed big torque permanent magnet motor transmission system

high speed motor + reducer + hydraulic coupler

Rated power(KW)



Rated torque(N·m)



Rated voltage(V)






Synchronous speed(r/min)






Power factor



Starting torque multiple



Max torque multiple







Due to the use of permanent magnet to provide magnetic field, rotor process is mature, reliable, size is flexible, and its design power range from dozens of watts to megawatts. At the same time, by increasing or decreasing the number of permanent magnets in the rotor, it is easier to change the number of poles of the motor, so that the speed range of the permanent magnet synchronous motor is comparatively wider.

The use of multi-poles permanent magnet rotor, the rated speed can be as low as single digit, which is difficult to achieve by ordinary asynchronous motor.

Especially in the  application environment of low speed and high power, permanent magnet synchronous motor can adopt multi-poles direct drive at low speed. Compared with ordinary motor plus speed reducer, the advantages of permanent magnet synchronous motor are prominent.

Direct drive type permanent magnet motor: due to the cancellation of reducer, motor output speed is low, low mechanical noise, small mechanical vibration, low failure rate, and the whole drive system is almost maintenance-free.

Asynchronous motor + reducer structure: it causes vibration, heating, high failure rate, large consumption of lubricating oil, high cost of manual maintenance; it will cause certain shutdown loss.

The special low-speed and high-power permanent magnet drive system adopts  optimal design: the motor   itself has a higher efficiency up to 93-97%, and a higher power factor up to 0.99, which     increases the proportion   of  active power in the  system. At the   same   time, the transmission efficiency of the whole equipment is higher than that of the high-speed motor + gearbox because no gearbox transmission is required.

For example, the average load rate of the motor in the whole running process from starting, running to stopping is about 40%, while the maximum load rate is less than 60%. Since the efficiency and power factor of the asynchronous motor are closely related to the load rate, when the load rate is lower than 50%, the efficiency and power factors drop sharply.The efficiency and power factors of permanent magnet motor are less affected by the load rate, and can still keep extremely high efficiency and power factor within the load rate of 20% ~ 120%.

Since conventional asynchronous motor starting torque multiple and maximum torque multiple are limited, in order to meet the requirements of heavy load start, a larger capacity asynchronous motor needs to be chosen,usually one or two grades power amplification required. During normal operation state, motor     is in light load operation, with relatively low efficiency and power factor.

Permanent  magnet  synchronous motor does not need additional excitation current because the rotor magnetic field exists all the time. The starting torque can be more than twice of the rated torque, which can meet the load requirements of heavy load starting.The efficiency and power factors of permanent magnet motor are less affected by load, and can keep extremely high efficiency and power factor within 20% ~ 120% of load rate.