18
turning the black dial on the overload relay to slightly higher number. (Do this
ng maintained to keep it from
verheating. A burnt out motor will usually draw an excess of current and trip the motor
or overheat in one spot. It may, however, overheat an internal connection
motor stamped class A can reach a temperature of 203°F on its shell; Class B can reach a
. Electrical Discontinuity.
ck for loose wires or
onnections. Check motor power circuits by visually turning current on and pushing in the motor
sulated screwdriver.
“H”. if nuisance tripping is occurring due to a higher ambient temperature, the trip point may be
raised slightly by
only after determining that the motor is not drawing higher than nameplate current. If current
draw is excessive the problem is in the motor, not the overload.
D. Motor burnt out.
All motor used on your grinder have a design life of many years. The motor most likely to fail is
the oil pump motor because it depends on the oil level bei
o
overloads, blow fuses,
and cause a wire to break loose. Checking motor circuit with an ohmmeter should locate any
internal breaks. An ammeter check on motor current on each of the three legs of a three phases
motor will show a shorted out section of winding by drawing more that the rated full load
current.
A maximum temperature at which a motor can be safely operated depends on the class of
insulation of its windings.
A
temperature of 239°F, and still be within the manufacturer specifications.
E
If all above checks have been made and one or more motors still do not run, check motor starters
and control panel wiring. Open control compartment and visually che
c
starter solenoid with a fully in
CAUTION
: Electrical connection or services to preclude personal injury or extensive
machine damage. All electrical service must be performed by an authorized Harig®
distributor Violation will void the warranty.
If motors run, check control circuit by turning off current and using an ohmmeter to check
control-wiring continuity against the electrical diagram. (The most likely cause of an open circuit
would be the starter solenoid coil or a faulty ove
rload relay.)
g. If it is necessary to remove the
ddle in order to get at the hydraulic fittings, lift table off the saddle.
s may be removed from fittings on the carriage, or the hydraulic unit taken
hoses are removed, tag them so that they can be reconnected to their proper fittings. Then
ard until it hits the cross feed stop, which pulls the bearing off the cross
If the motor does not run with the starter solenoid held in, turn off current and check power
circuit continuity.
Tighten all loose fitting. Replace any defective hose or tubin
sa
The hydraulic hose
out of the compartment and placed in a position to allow the saddle to be handled within a range
that the hose will flex.
If
crank the saddle all the way up to the column. Remove the screw in the end of the cross feed
hand wheel, loosen setscrews in the side of the hand wheel and pull the hand wheel off its shaft.
Now pull the saddle forw
feed screw shaft. Remove the tubing connector that fastens the lubricating oil line between the
base and the saddle from the saddle fitting. The saddle can now be lifted off the machine.
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