General Instructions for Use of Pacific DC Micro
Motors
1. If silicon materials, which contain low molecular silicon
compounds, adhere to the motor's commutator,
brush or other parts, then upon rectification of the electric
energy the silicon breaks down into SiO2, SiC
and other constituents which produce a rapid increase in the
contact resistance between the commutator
and brush. Therefore great care should be taken when silicon
material is used in a unit and check well at
the same time that such binding agents or sealing materials
are not generating gases of detrimental nature,
whether used for motor mounting or applied during your product
assembles. Care must be taken for an
optimum selection, especially when using those of cyanicadhesive
and sulfur gas.
2. When mounting your motors by means of binding agents, DON'T
allow any adherence to the bearings nor intrusion into the
motors.
3. Axial thrust on the output shaft could have an adverse
effect on the motor life. i. e. As is produced by worm gears,
fans, etc., Check the service life expected under the actual
operating conditions by testing the motors installed in your
application products. For heavy thrust loads, consider using
something mechanical to retain the shaft end.
4. There are occasions when the internal resistance of the
motor driving power source (Which contains an electrical circuit)
can influence the life span of the motor. In instances where
there is a low input of voltage to the motor, the internal
resistance of the power source is large which may well result
in an inferior motor after a short time, conversely in instances
where high cyclic voltages are applied, this internal resistance
is small and the motor life span is shortened. When the temperature
deviates from the normal room temperature as is the case in
low and high temperature situations, please note the conditions.
5. Motor life may be affected adversely by heavy radial load
such as produced by rotating eccentric cams, etc.,and also
by vibration given from outside. DO check over such negative
factors by testing the motors to the actual operating conditions
in your application products.
6. If when mounting the motor and assembling the unit, equipment
which emits ultrasonic waves is used there is a danger that
some of the internal parts of the motor might be damaged so
please take care.
7. DON'T store motors under environmental conditions of high
temperature and extreme humidity. DON'T keep them also in
an atmosphere where corrosive gas may be present, as it may
result in malfunction.
8. Ambient and operating temperatures exert an affect more
or less on motor performance and life. DO pay
particular attention to the surroundings when it is hot and
damp.
9. When press fitting a pulley, gear etc., onto the motor
output shaft, always support the shaft at the other end or
its retaining metal pad in a proper and correct way.
10. When soldering, BE SURE to finish your work quickly so
as not to develop plastic deformation around the motor terminals
nor to give them any forced bend or inward depression. In
doing so, special care must be
taken not to allow solder debris and flux to spatter into
motors and precautionary measures should be taken
if necessary, by covering up all the nearby holes and apertures.
Any motors having snap-in terminals must
also be attended carefully so as not to get flux in along
the terminals, as it may cause failure in electrical
conduction.
11. DON'T leave motor shaft locked while power is applied,
as even a short-time lock-up may cause excess heat build up
resulting in burning damage to the motor depending on its
specifications. |
Basic Knowledge of Electromagnetic
Force
Electromagnetic Force
The direction of magnetic flux produced by a permanent magnet
is always from N-pole to S-pole. When a conductor is placed
in a magnetic field and current flows in the conductor, the
magnetic field and the current interact each other to produce
force. The force is called "Electromagnetic force".
The fleming's left hand rule
determines the direction of the current, the magnetic force
and the flux. Stretch the thumb, the index finger and the middle
finger of your left hand as shown in Fig. 2. When the middle
finger is the current and the index finger the magnetic flux,
the direction of the force is given by the thumb.
Magnet field produced by current The magnetic
fields produced by the current and the permanent magnets works
to produce electromagnetic force. When the current flows in
the conductor toward the reader, the magnetic field in the CCW
direction will be produced around the current flow by the right-handed
screw rule. Interference of a line of
magnetic force The magnetic fields produced by
the current and the permanent magnets interfere each other.
The line of magnetic force distributed in the same direction
acts to increase its strength, while the flux distributed in
the opposite direction acts to reduce its strength.
Electromagnetic force production The
line of magnetic force has a nature to return to the straight
line by its tension like an elastic band. Thus, the conductor
is forced to move from where the magnetic force is stronger
to where it is weaker.
Torque production Electromagnetic force is obtained from the
equation; |