¡ôAllowable sustained slip rates

Powder Clutch and Brake Application

Due to the feature of the magnetic powder clutch and brake, they have been widely used in paper making, printing, plastic items, rubber industry, textile industry, printing and dyeing, wire and cable, metallurgy industry and tension control of winding and unwinding in roll material processing industry. A complete set of schematic of tension control system is as follows.

Note:

The magnetic powder clutch can be also used in buffering start, overload protection, speed adjustment; the magnetic brake can also be used in test loading and braking of transmission machinery.

Design reference

First, let us learn the meaning of the following words:

1. Slip rotational speed: the speed difference between input shaft and output shaft is magnetic powder clutch, the rotational speed of output shaft for magnetic powder brake.

2. Slip powder: the powder generated from the slip rotational speed when the magnetic powder clutch or brake transfer torque.

The selection of the magnetic powder clutch or brake rely on the maximum required torque and rotational speed. Because the temperature of all parts will rise when the slip power is converted into heat, it is guaranteed that the actual slip power is less than the rated value.

Tension Controllers

Tension and Torque Controllers automatically compensate for changes in roll diameter, speed and other process variables.

What is Web Tension Control ?

Web tension control can be defined as the maintenance of a set amount of web tension (pull or force) for a material being processed. Often measured in oz, lbs, grams, kg, or newtons ¡ª proper tension must be maintained to prevent stretching, wrinkling, breaking or inconsistent registration of material during printing or converting processes.

Web tension control improves uniformity in coating applications and material lamination while decreasing the incidence of rewind defects such as crushed cores, starring and telescoping. When web tension is under control it can enable processes to run at higher speeds while reducing scrap, delivering a rapid return on investment that boosts producers' long term profitability.

Where is web tension control most commonly used?

Web tension control is most commonly used in three zones: Unwind (infeed), Intermediate (process), and Rewind (take up).

In the unwind zone, infeed roll hold-back torque is often controlled by an electric or pneumatic brake. The web strain or tension resulting from this torque is regulated by a closed-loop controller to prevent web drooping, stretching or wrap-up incidents ahead of transiting to the intermediate zone.

Proper maintenance of intermediate zone tension is often critical to ensuring the quality of coating, laminating, curing, treating or slitting processes. This zone is typically controlled by a set of driven nip rollers which dictate line speed to the entire system. This speed reference is matched in the unwind and rewind by virtue of having to accelerate or decelerate in order to maintain a desired tension set point.

Proper tension in the rewind zone ensures under or over-tight rolls and their associated defects are prevented. Rewind zone torque is often controlled by the motor drives of center or surface winders. Implementing progressive taper tension techniques during winding is an effective way to ensure finished rolls maintain spring tension stability and do not experience material shift and core deformation during handling and storage.

From process start to finish, it's clear that reliable web tension control is the key to ensuring maximum system efficiency and quality of finished products.

Typical tension control solutions incorporate:

• Sunrise Automatic tension controller such as the LTC-858A,LTC-858A

• Sunrise Tension sensor such as LS series or LC series tension sensor

• Sunrise A Pneumatic Brake, Magnetic Particle Brake, Clutch

Magnetic Powder Brake

Sunrise’s magnetic powder brake is based on the electromagnetic principle and uses magnetic powder to transmit torque. When the magnetic coil is not conducting electricity, the torque will not be transmitted from the input shaft to the output shaft, but if the coil is magnetized, the magnetic force will attract the magnetic powder to produce the hardening phenomenon, and the torque will be transmitted between successive slides. Moreover, it has the feature that the excitation current and the transmitted torque are basically linear. It has nothing to do with slip and can transmit a certain torque, and has the advantages of fast response, simple structure, no pollution, low noise, no shock vibration, energy saving, etc. It is a multi-purpose automatic control element with superior performance.

Why Select Magnetic Powder Brake

1. High-precision and wide torque control, high accuracy control, the transmitted torque in the correct proportion to the exciting current form a high precision control.

2. Constant torque and fast response, Adopting imported super alloy magnetic powder with superior heat resistance, the output torque is constant, fast induction speed, and can work at high pass.

3. Quiet and stable operation, using high temperature resistant coil and special bead grease bearing, smooth running, no shock, no vibration, and no noise.

4. Novel design, excellent heat dissipation, long service life, Adopting uniform cooling structure of heat deformation and excellent heat dissipation design, low temperature rise and long service life.

Applications

1. Maintain, connection,

2. Braking, variable speed

3. Positioning, continuous sliding

4. Cushioned starting, torque limiting,

5. Load prevention

6. Precise tension control.

Installation and Use

1. Magnetic powder brake adopts DC as excitation power supply.

2. Magnetic powder brakes do not support the installation method of the radial bearing main power transmission.

3. For the first use of the magnetic powder brake, power off after 10 seconds of operation then power on, repeating several times. ensuring the fluidity and uniform distribution of magnetic particles.

4. The magnetic powder brake cannot be used exceeding normal torque and rotation speed, otherwise the life of the magnetic powder will decrease sharply.