Safety · 2026-11-11 · 5 min

The brake that holds when the battery dies

An electromagnetic brake is normally closed: no power means locked, not free. That one design choice decides what happens on a slope when a connector comes loose.

Almost every power chair sold in Europe or North America uses an electromagnetic brake, and almost no listing explains it. It is worth understanding, because it is the part of the chair that behaves correctly when everything else fails.

How it works

The brake is spring-applied and electrically released:

Power off — a spring clamps the brake. The wheels are locked. This includes the moment the battery is removed or the key is turned off.
Power on — a coil pulls the armature away and the chair rolls freely.

That is the opposite of a car handbrake, and it is deliberate. A chair parked on a ramp with a flat battery does not roll away. It also means a chair cannot be pushed while switched on — which is why every chair has a manual freewheel lever for the carer.

Where it matters in the real world

Ramps and kerbs. Releasing the joystick stops the chair and applies the brake. On a slope this is what holds the chair while the user opens a door.
Transport. With the chair switched off, the wheels are locked, so it does not move inside a van.
Battery removal for charging. Pull the pack and the chair stays put. No chock needed.

A chair without an electromagnetic brake is not a cheaper chair — it is a different product with a different risk profile. If a quotation does not state the brake type, ask. The answer should be a single phrase: electromagnetic, normally closed.

The freewheel lever is not a brake

Every chair has a lever that disengages the motor so a carer can push it. Users confuse this with the brake. Two consequences worth putting in your manual and your training:

Never leave the chair on a slope with the lever disengaged. The brake is bypassed and nothing holds it.
Never sit in a chair with the lever disengaged. It will roll.

What to check on the sample

Put the chair on a ramp, switch it off, and try to push it. It should not move. Then release the lever and push: it should roll. If both states feel the same, the brake is not working and the sample should go back.