Torsional Vibration; Liquid Temperature And Overheating; Pump Vacuum Check; Bearing Temperature Check - Generac Power Systems MAGNUM MTP4SZ Owner's Manual

Torsional Vibration

Torsional vibration is a periodic, reversing twist in a torque
transmitting member such as a shaft. This twisting is
superimposed upon the rotation of the shaft. Any rotational
system has at least one torsional natural frequency, the
frequency at which the shaft will twist back and forth if a
torque is instantaneously applied then released. Internal
combustion engines deliver torque in a periodic or pulsing
manner and consequently are very effective exciters of
torsional vibration. If an engine/pump set operates too near
a critical speed, severe damage to the pump, engine or
related components can result. This is not indicative of a
defect in any of the components; rather it is a characteristic
of any rotational system.
CAUTION
Equipment Damage. Always run pump with water
in the priming chamber. Failure to do so will result
in equipment damage and/or failure.

Liquid Temperature and Overheating

The maximum liquid temperature for this pump is 160 ºF
(71 ºC). Do not apply it at a higher operating temperature.
Overheating can occur if the pump is operated with the
Owner's Manual for Wet-Prime Trash Pumps
Figure 3-52. 6 Inch Pump Flow Rate Chart
valves in the suction and/or discharge lines closed.
Operating against closed valves could bring the liquid to a
boil, build pressure, and cause the pump to rupture or
explode. If overheating occurs, stop the pump and allow it
to cool before servicing it. Fill the pump casing with cool
liquid.

Pump Vacuum Check

With the pump inoperative, install a vacuum gauge in the
system. Block the suction line and start the pump. At
operating speed, the pump should pull a vacuum of 20 in.
(67.7 kPa) of mercury or more. If it does not, check for air
leaks at the suction piping gaskets.
(000280)

Bearing Temperature Check

Bearings normally run at higher than ambient temperatures
because of heat generated by friction. Temperatures up to
160 ºF (71 ºC) are considered normal for bearings, and
they can operate safely to at least 180 ºF (82 ºC). Measure
the bearing temperature with a contact-type thermometer.
WARNING
Personal Injury. Do not operate pump with flow
completely restricted. Doing so could cause pump
casing to explode and could result in death or
serious injury.
Operation
01642
(000273)
37