13
Symptoms
Possible Causes
All copper plates turn black
The pressure of brush is incorrect.
The commutator turns black in a
certain order and in groups
Short circuit in the commutator or armature coil; poor welding or
disconnection between the commutators and the armature coil.
The commutator turns black
The central line of the commutator deviates or its surface is not
round and smooth.
The brush wears out, turns colors and
become broken
The motor vibrates; the clearance between the brush and its holder
is too big; the clearance between the brush and commutators is
too big; the mica between different commutators extrudes; the
brush is made by wrong materials; the brush is the wrong type.
Big sparks
The motor is overloaded; the commutators are not clean, round
or smooth; mica or some commutators extrude; the brush is not
ground properly; the brush is the wrong type; the brush is jammed
in the brush holder; the brush holder become loose or vibrating;
the polarity and sequence of magnetic poles is wrong.
The brush and its wires get hot
Big sparks of the brush; poor contact between brush and soft wires.
The brush is noisy
The surface of the commutators is not smooth.
Speed Controller
Speed Controller Maintenance
The speed controller of the vehicle is wholly imported, which adopts high frequen-
cy MOS technology to realize the control of speed, torque and brake with smooth-
ness, silence, and high energy efficiency.
When the vehicle starts, the controller will inspect signals from the accelerator.
If signal exceeds 20%, the HPD (protection unit in the controller) will prohibit the
output of the controller. The controller will self-check when the vehicle is running.
If any defect inspected, the controller will stop the vehicle to protect the operator
and the vehicle.
Brake System Maintenance
Depress the brake pedal with a force of 65 lbs. The pedal travel shouldn’t exceed
2/3 of the full free pedal travel.
The clearance for the brake plate is self-adjusted. Under a force of around 45 lbs,
the parking brake handle should be fixed in one gear from 5 to 10 ratchets. When
the brake handle is released completely, the brake function will stop. Inspect and
change brake shoe, and add lubrication into the brake bearing periodically.
Summary of Contents for BN72-11-AC-D
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