Rotor - Husqvarna DM 330 Workshop Manual

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ROTOR

Functional test
Preparations
Remove the inspection cover to the carbon brushes.
Connect a measuring cable to each carbon brush. (You do not need to be
concerned that the stator is connected at the carbon brushes as the stator's
circuit board is broken at the circuit board and is therefore not affected by the
measurement.)
Measuring cables
Use short measuring cables and lay these close to each other: the easiest way is
to twist them. Cables run in a coiled way give incorrect readings.
230 V
Inductance measurement – Henry (H)
Inductance measurement is applied to check the condition of the rotor. The
dimension is "Henry", abbreviated H (1 H = 1000 mH). Resistance measure-
ment (ohm) produces no usable results.
Testing
Set the measuring instrument to measure mH. Turn the rotor shaft slowly once
ensuring you obtain the measured values for each winding of the rotor.
Measured values
230 Volt: Typical measurement value for a full rotor is around 13 mH for
DM330 and 9 mH for DM340. 120 Volt: DM330 produces around 2.6–3.0 mH.
120 V
The inductance values may vary a lot between the various measurement
instruments and machines. Pay special attention therefore to the differences in
the values during the test, rather than the absolute values.
Dismantling
Remove the wearing ring.
Carbon brush holder
Remove the carbon brushes and
the carbon brush holders.
Motor cover
Remove the screws.
Earth connector
Remove the cover and the screw
to the earth connector.
Dismante the rotor
Knock or press out the rotor
towards the bearing's outer ring.
Dismantling
First remove the wearing ring to the
radial seal. Use a bearing puller or a
small standard puller.
The bearing puller can be acquired
from Husqvarna, item no. 531 00 48-67.
Rem: The wearing ring does not need
removing unless the rotor is to be sepa -
rated from the motor cover.
Carbon brush holder
Remove the carbon brushes and the
carbon brush holders. (The ball bearing
holder has a larger diameter than the
distance between the carbon brush hol-
ders.)
Motor cover
Remove the four screws to the motor
cover.
Earth connector
Remove the cover.
Remove the screw to both earth connec-
tors. 120 V machine has one connector.
Warning!
You must not dismantle the rotor by
knocking the magnet on the shaft!
Dismantle the rotor
Use a socket that fits the bearing's outer
ring and knock or press out the rotor.