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HYDROFIT™ Owner’s Information Manual
WARNING: The use and ownership of this work is defined in the legend upon the front page hereof.
Solid-State starting uses power semiconductors instead of contactors. Unlike contactors,
power semiconductors can be switched on and off at very high speeds and at specific
times during the three-phase 60 Hz power cycle. By controlling the semiconductor’s
on/off function during the power cycle, the current can be controlled.
Typically, the solid-state starter will be adjusted to provide a higher starting current than
is available with Wye-Delta. This additional torque allows the motor to be brought up to
operating speed quickly and smoothly. Motor operating speed for solid-state starting is
reached faster than with Wye-Delta. An additional benefit is that since the solid-state
starter does not use contactors, the noise of contactors opening and closing is completely
eliminated. Maintenance costs associated with contactors are also eliminated.
Electrical devices are always susceptible to high voltages and starting currents.
Your elevator motor is no different. There are protective devices available to monitor
conditions. Should a power supply or an over-current problem arise, the protective
devices would allow the elevator to safely shut itself down.
One protective device is the reverse-phase relay. The reverse-phase relay continuously
monitors three-phase input power lines for the following abnormal conditions:
• Loss of any phase
• Low voltage on any or all phases
• Phases reversed from proper sequence
• Phase imbalance
The reverse-phase relay is built into the Solid State Starter. If any of the above
conditions are encountered, the device activates and prevents the condition from
traveling to the starter/contactor and motor.
The current overload relay is another device used. This device is also part of the Solid
State Starter. As mentioned earlier, the initial current drawn by the motor when first
starting can be five to eight times its normal operating current. The current overload
function monitors the amount of current passing through each of the lines of the three-
phase power supply. It activates within five seconds if the high starting current continues.
When activated, it turns off the starter to de-energize the motor.
The Pump
The pump is directly coupled to the output shaft of the motor. It is rated for 500 pounds
per square inch (psi). The pump converts the mechanical energy produced by the
rotating shaft of the motor to hydraulic energy, the flow of oil. The pump is classified as a
positive-displacement type, due to its ability to maintain
a constant output regardless of oil pressure.
The pump/motor assembly is submersed at the bottom of the oil tank. The pump has an
inlet line which accepts oil from the tank and an outlet line, which passes the oil to the
control valve. The rate of the oil flow in the pump is typically between 56 and 120 gallons
per minute. The rate required depends on the elevator’s plunger diameter and speed. Oil
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