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Only use UL listed insulated cables with the following designations: RHH, RHW,
RHW-Z, XHH, XHHW, XHHW-Z or XLPE. Do not use designations THHN or any others
beginning with ‘T’.
When the Total wiring lengths between a VFD and a motor or multiple motors
exceeds 100 feet, shaft currents and motor noise can occur. This can be eliminated
or reduced by the use of special wires and/or a dv/dt output filter.
The use of a VFD to control motor speed induces harmful electrical voltages on the
motor shaft, eventually leading to bearing failure. Rocore and motor manufacturers
recommend using ceramic-coated bearings and a shaft grounding device to extend
the life of the motors.
9.
A deceleration control must be included in multi-speed magnetic starter panels when
using 2-speed motors. Deceleration control automatically provides, by use of a timer,
motor deceleration when changing from high speed to low speed. The timer allows
the motor to decelerate from high speed to a lower speed before automatically
restarting the motor in low speed. Lack of deceleration control can lead to burned
motor windings, which is not covered by Rocore’s warranty.
E.
COOLANT LEVEL SWITCHES
To add a coolant level switch to a radiator, see Figures 12 or 13.
If you are using a vertical radiator, the installation is shown in Figure 12. The top
connection of the switch is piped to the lowest acceptable coolant level port in the top
tank. The lower connection is piped to a drain port in the radiator bottom tank. The
lower connection should not be close to the radiator outlet.
If you are using a horizontal radiator or a vertical radiator with a surge tank, the level
gauge is installed on the surge tank as shown in Figure 13. Both the top and bottom
connections are piped into the high and low ports of the surge tank.
F.
FILLING
Thoroughly clean and flush the coolant system (piping, radiator and engine) before
filling with new coolant or replacing old coolant. This is especially important if the
coolant previously in the system is incompatible with the new coolant. Before coolant
additives can be effective, the cooling system must be free of rust, scale and other
deposits.
Before the cooling system is filled, always premix the water, supplemental coolant
additives and antifreeze.
CAUTION! Do not fill the radiator or surge tank all the way to the top because as
the system heats up, the coolant will expand and hot coolant or steam will be forced out
of the overflow hose. When the system heats up and the coolant expands, the tank
should be 2/3 to 3/4 full. This reserves 1/3 to 1/4 of the tank volume for coolant
expansion, drawdown and deaeration.
The coolant level should be checked after initial startup to account for any air pockets
created during initial filling. Add coolant as required.
