PPSTinc 12.5-135/400, User Manual

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6. Load station tuning.
WARNING: Always ensure that
both the power supply’s circuit
breakers are turned OFF when
adjusting
heat station
components.
This section describes the
procedures for tuning the heat
station so that full power will be
obtained at the desired frequency.
6.1 Initial setup.
The following are the steps to be taken for the initial setup of the load station for a new
heating coil and/or load:
1. Install all twelve the load station capacitors.
2. Install the turns-bar in the 12 turns position and remove the two shorting bars.
Section 6.3 describes the procedures for changing heat station components.
6.2 Tuning.
WARNING: Never run the power
supply with an open coil. Doing
so may damage the inverters.
This section provides the procedures required for the tuning of the heat station for a
specific heating coil and load. It is assumed that the initial setup of the heat station has
been completed as described in section
6.1
The aim of this exercise is to have the unit operating at full power (25kW) at the desired
frequency (user specified between 135 kHz and 400 kHz) without any indicators lit.
1. Ensure that the heat switch on the front panel is OFF state, that the program
“POWER CONT=LOCAL” and that the power level knob is turned completely
counter clockwise. Check that the cooling water is turned on. The unit will not deliver
power if the minimum differential water pressure specification is not met, a flow trip
will occur.
2. Turn on the control breaker. The green OFF indicator should light up and the LCD
display should indicate that the control circuitry is powered up. Press the reset
button if any trip (red) indicators are lit. Ensure the emergency stop button is not
pressed in and the door is closed. Turn on the Main circuit breaker.
3. Press the ON button of the HEAT switch. Turn the POWER knob until the unit
delivers approximately 10% power. If the frequency of the unit is not slightly above
the desired (user specified) frequency, adjust the capacitance of the heat station and
return to step
1. The required capacitance change is inversely proportional to the
square of desired frequency change. Example: To increase the frequency by 40%,
20