1. Working principle Magnetic powder brake and magnetic powder clutch are based on electromagnetic principle and use magnetic powder to transmit torque. It has a substantially linear relationship between the exciting current and the transmitted torque. It can transmit a certain torque under the condition that has nothing to do with the slip, and has the advantages of fast response speed, simple structure, no pollution, no noise, no shock vibration and energy saving. It is a multi-purpose, superior performance automatic control element. Magnetic powder brakes are widely used in various mechanical braking purposes, power test loading, unwinding tension control, etc. Magnetic powder clutches are widely used in buffer starting, overload protection, speed regulation, and tension control of winding in winding systems.
2. Basic characteristics a. Excitation current-Torque characteristics The excitation current and torque are basically linear. The torque is controlled by adjusting the excitation current, and its characteristics are shown in Figure A.
b. Speed-torque characteristic Torque has nothing to do with the speed and maintains a fixed value. (When the exciting current is constant, the rotation is not affected by the change of the speed within the allowable slip speed range.) There is no difference between static torque and dynamic torque. Its characteristics are shown in Figure B.
c. The allowable slip power of the magnetic powder brake is a fixed value when the heat dissipation condition is constant. When its actual selection and selection, the practical slip power must be within the allowable slip power. When using a high speed, reduce the torque. Its characteristics are shown in Figure C.
Example: CZ-10 magnetic powder brake:
Rated torque: M = 100N.m
Slip power: P = 3KW
Then the speed: n = 1500rpm continuous running rigid allowable torque should be: M = 9550P / n = 9550 × 8/1500 = 19.1Nm (where 9550 is the unit conversion constant)
That is, if the speed is increased to 1500 rpm, the torque can only be used for continuous operation below 19N.m. Otherwise the temperature rises continuously.
The selection of magnetic powder brakes and magnetic powder clutches is generally based on the required maximum transmission torque, and care should be taken to ensure that the slip power used in actual use should be less than the allowable slip power of the technical parameters. The larger the point, the longer the use. life. Calculation formula:
Actual slip power:
In the case of a sky shift mechanism, the product of the maximum tension required for the winding material and the maximum winding radius should not exceed the rated torque of the brake.
The choice of magnetic powder brake is related to its position. On the premise that the slip power is matched, the magnetic powder clutch is placed at a high speed, and the cap can choose a smaller size. If it does not match, it should be placed at the low speed end (middle or rear) of the mechanism to increase the working torque to reduce the slip speed. The selection of magnetic powder clutch is more complicated, and users can call for consultation.
4. How to use Magnetic powder brakes and clutches use DC power as the excitation power source. Our company produces sk-1 \ sk-2 \ sk-3 \ sk-5 manual tension controller, PSN power amplifier and 2k-1 \ 2k-2 full-automatic tension controller for its dedicated control power supply.
Magnetic powder brakes and magnetic powder clutches often use magnetic powder to gather somewhere during transportation, and sometimes even "stuck". At this time, as long as the entire brake or clutch is turned 180 degrees, tap with a wood hammer a few times to loosen the magnetic powder. Or use the lever to rotate the shaft left and right, as long as it is turned. It is recommended to choose a clearance fit for the coupling fit of the coupling. Axial tapping is strictly prohibited. Before use, run-in operation should be performed. First, run at a rated current of about 20% for a few seconds, and then power off and then on again. Brake over 500N.m. Some magnetic particles are installed separately. In running-in, the magnetic powder can be injected gradually from the upper magnetic powder filling port without rotating the exciting current.
After the water-cooled magnetic powder brake and clutch rotate, there should be no pressure at the water outlet (water pressure is not greater than 1.5 square meters). The rotor has a water-cooled magnetic powder brake, and there is a small drip hole on the inner end of the outlet pipe. If drip water is found, the water seal of the same model should be replaced in time, and do not block. Naturally cooled or air-cooled brakes, clutches, and surface temperatures must not exceed 70 degrees. Forced cooling can be achieved with fans or blowers. If the margin is large, the rotation speed is low, and the surface temperature is low, water may not flow.
Magnetic powder brakes, clutches, and couplings should be used as much as possible when used. The use of radial transmission bearing transmission is not supported. Such as gear pulleys, etc., if it is really needed, it is recommended to increase the support of the gear pulley in the axial direction.
Magnetic powder brakes and clutches that have not been used for a long time should be stored in a ventilated and dry place for more than one year. It is recommended to perform a comprehensive maintenance before use.
When you replace the new magnetic powder, please inform us of the product's specifications. Our company can accurately provide the specifications and quantity of the magnetic powder accordingly. At the same time, our company undertakes the maintenance and repair business.