Ransburg Voltage Master 2 78789_LEPS5001 - Manual (Page 30)

MASTER CONTROL
BOARD FUNCTIONS
A general description of the Master Control Board
operation only is included in the following. The
Master Control PC Board performs the following
functions:
1. Filtering and transient protection of the power
supply KV and current feedback signals.
2. Properly scaled and buffered output signals to
the front panel digital displays.
3. Conversion and buffering of the remote control
input and output signals.
4. Supplies the HV ON overload inhibit timer so
that the system can initially charge to voltage
without nuisance overloads. An LED located on
the board is active during the inhibit cycle.
5. Compares the overload setting with the actual
high voltage output current and generates a latched
overload condition that results in high voltage
shutdown. A factory set potentiometer is located
on the board that fine tunes the overload trip point.
This should only be adjusted by trained Ransburg
personnel or with instruction from Ransburg or an
Ransburg representative.
FRONT PANEL BOARD
FUNCTIONS
(Refer to Figure 12)
The front panel Door Board contains the local
operator controls, digital display interfaces, dis-
play scaling adjustments (factory set), and the
overload full scale range select switch. A buff-
ered +5VDC supply voltage is generated from
+15VDC input for the displays.
MOTOR CONTROL
BOARD
The LECU4013-00 Motor Control PC Board As-
sembly receives the 0-10VDC KV feedback signal
from the power supply through wire #34. This
signal is compared to the requested KV setpoint
signal supplied from the control unit front panel or
from a remote source. The resulting error signal
is used to drive the bi-directional motor, that is
connected to the variable transformer (VAT1) shaft,
in the direction required to produce the requested
high voltage.
A limit switch, located in the box that surrounds
the variable transformer, rides on a cam that is
attached to VAT1. The cam will activate the limit
switch in the “home” position and in the “over-volt-
age” position. The motor control board will always
rotate VAT1 counterclockwise to the “home”
position when KV is turned OFF or AC power is
supplied to the control panel. It is important to
note that the overload inhibit timer is activated
only on the HV ON command signal and not at
the point where VAT1 starts from the “home” po-
sition. Therefore, if a HV ON command is given
BEFORE VAT1 has had a chance to reach “home”
from a previous HV OFF or overload reset, the
inhibit timer may elapse before VAT1 can reach
the “home” position and return to the HV setting.
This may cause an overload to occur since the
overload timer elapsed before the system has had
a chance to initially charge.
The Motor Control Board will cause a power
supply overload in the event of an overvoltage
condition or if there is a loss of the power supply
feedback signal.
Also located on the Motor Control board is a se-
lector switch that determines if the analog output
signal for actual KV is 0-10VDC or 4-20ma. Refer
to "Analog Control and Monitoring Signals" in the
"Installation" section of this manual and Figure 9.
Voltage Master 2 - Operation
26
Ransburg
CP-02-02.6