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Permanent-Magnet Brakes

Permanent-magnet brakes apply braking torque using a fixed magnetic field generated by permanent magnets — not an energized electromagnetic coil. Because the magnetic field is always present, these brakes hold or resist rotation without requiring continuous electrical power.

The three Ogura series in this category use permanent magnets as the torque source but differ in how that torque is transmitted and whether any electrical connection is needed at all. The PMB is a friction brake that engages by default and requires a DC voltage to release. The PHT and OPL use non-contact magnetic principles — hysteresis and magnetic particle respectively — and require no electrical connection of any kind. Torque in the PHT is user-adjustable; torque in the OPL is factory-set.

These units are suited for applications requiring a default braked or tensioned state with zero power consumption, including printers, copiers, ATMs, ticket kiosks, medical equipment, and light positioning systems.

Series Comparison Table

Series	Operating Principle	Contact Type	Power Required	Torque Setting	Torque Range	Typical Application
PMB	Permanent-magnet friction	Friction contact	DC voltage to release only	Fixed (flux-tunable)	Contact Electromate	Industrial and mobile braking; medical; portable equipment
PHT	Permanent-magnet hysteresis	Non-contact	None	User-adjustable	Up to 62 in-lbs	Tension control; paper feeds; lab equipment; no-wear applications
OPL	Permanent-magnet magnetic particle	Non-contact	None	Factory-set	Up to 3.5 in-lbs	Paper feed overload protection; printers; copiers

Permanent-Magnet Brakes for Purchase & Quote:

PMB Series Electromagnetic / Permanent-Magnet Brakes

Torque Range: 0.292–22 ft-lbs | Max RPM: 5000–10000 | Bore: up to 35 mm | 24 VDC permanent-magnet brake

$339.00

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PHT Series Permanent-Magnet Brakes

Torque Range: 0.0025–5.16 ft-lbs | Max RPM: 700–10000 | Shaft: 3–16 mm | Permanent-magnet brake (no power required)

$363.00

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OPL Series Permanent-Magnet Brakes

Torque Range: 0.022–0.292 ft-lbs | Max RPM: 200–400 | Shaft: 8 mm | Permanent-magnet brake

$42.00

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Permanent-Magnet Brakes – Frequently Asked Questions

How does a permanent-magnet brake work?

A permanent-magnet brake uses a fixed magnetic field from permanent magnets to apply braking torque without requiring continuous electrical power. Depending on the series, torque is transmitted through friction contact (PMB), magnetic hysteresis without contact (PHT), or magnetic particles without contact (OPL). The PMB requires a DC voltage only to release the brake. The PHT and OPL require no electrical connection at all.

What is the difference between the Ogura PMB, PHT, and OPL brake series?

The PMB is a friction permanent-magnet brake that engages by default and releases when DC voltage is applied. The PHT is a non-contact permanent-magnet hysteresis brake — torque is transmitted magnetically with no friction surfaces and no electrical connection required. Torque is user-adjustable on the PHT. The OPL is a non-contact permanent-magnet magnetic particle unit with factory-set torque and no electrical connection required. It is commonly used for paper feed overload protection in printers and copiers.

Do permanent-magnet brakes require power to hold a load?

No. Permanent-magnet brakes apply torque through a fixed magnetic field that is always present. The PMB series requires DC voltage only to release the brake — not to hold it. The PHT and OPL series require no electrical connection at all and operate entirely on permanent magnets.

What is a permanent-magnet hysteresis brake?

A permanent-magnet hysteresis brake transmits torque through the magnetic hysteresis of a steel disc — no friction surfaces, no electrical connection, and no wear particles. The Ogura PHT series delivers consistent, repeatable torque that is unaffected by slip speed and is user-adjustable over a wide range. These units are suited for tension control, paper feeds, lab equipment, and applications where wear particle contamination is not acceptable.

What are permanent-magnet brakes used for?

Permanent-magnet brakes are used in applications requiring a default braked or tensioned state with no continuous power draw. Common applications include printers, copiers, ATMs, ticket kiosks, medical equipment, portable devices, paper feed systems, and light positioning equipment. The non-contact PHT and OPL series are suited for environments where wear particles would contaminate the machine or product.