PowerTec 2000C Instruction Manual page 54

6.5 CURRENT CONTROLLER
Refer to the BLOCK DIAGRAM in Figure 31.
The Current Controller Board (part # 4001-141108-
010) contains the main operational and protective logic of
the Brushless DC motor control. It develops low level
power supplies (+24VDC and -24VDC) from AC power
supplied through the cable to the base driver board and
develops its own regulated supplies (+15VDC, -15VDC,
and +5VDC). The Current Controller has these functions:
1. It locks out the drive on a fault if it receives a
signal from the capacitor board (Over or Under Voltage or
OverCurrent), from the base driver board, Power Loss, or
from its own fault monitor . When in the fault mode it turns
off an optical coupler which communicates with the out-
side world (TB1 terminals 12 and 13). This coupler is
normally turned on. STOP is NOT a fault mode.
A fault is reset when the run command at TB2
terminal 4 is removed if the RESET SELECTOR is in the
INT position (the left two pins). If the jumper is on the
right two pins (the MAN position), the control will not
reset a fault unless input power is turned off and then on
again, or the jumper is moved to the middle two pins
momentarily (no RUN command may be present when this
is done!) and then placed on either the left two pins
(internal reset) or the right two pins (manual reset). The
drive will not run with the jumper on the middle pins.
2. It determines if an outside frequency is called for
(+24VDC between TB1-10 (+) and TB1-9(-), and substi-
tutes the frequency at TB1-11(+) andTB1- 9(-) for the
internal VCO frequency.
3. It accepts a run enable request from the Speed
Controller Board, and, if there is no fault, it will return an
ENABLE signal. The enable request is interlocked through
a connection on the Current Sensor Board.
4. It compares a current reference command (veloc-
ity error) from the Speed Controller Board against the
current signal received from the Current Sensor Board. If
the actual current is greater than the allowed current , the
current output is limited by adjusting the pulse-width
modulation. Current limit is checked every PWM pulse.
5. It samples the current in a sample and hold
circuit, which may be monitored externally between TB1
terminals 14(-) and 16(common). The level is calibrated
by the Horsepower Calibration resistor on the Current
Sensor Board (-2VDC = 150% of full load current).
6. It receives the encoder signals from the motor.
There are five channels. Three channels are used to
determine shaft position (HS1, HS2, and HS3). The Cur-
rent Controller Board generates complementary signals
and feeds all six signals to the EPROM in the L3 socket (a
141-300 is standard). The position channels of the en-
coder are used by the Current Controller to determine the
output transistor firing sequence. There are three lights on
the Current Controller Board which monitor the position
encoder channels (labelled HS1, HS2, and HS3).
© copyright 1992, 1996 by Powertec Industrial
Motors
HS4 and HS5 are used to regulate speed and to
determine direction of rotation of the motor. The
signals from HS4 and HS5 have the same pulse rate,
but they are in "quadrature" (90° out of phase ). The
Current Controller Board detects leading and trailing
edges of each of the speed signals and combines them
to allow the EPROM to select a X4, X2, or X1
multiplier rate. The standard EPROM (141-300)
multiplies the single channel pulse rate by four (X4).
For a four-pole motor, the sixty pole encoder wheel
supplies a 30 PPR rate in each of the channels. The
standard EPROM multiplies this by four to supply a
120PPR feedback rate to the Speed Controller Board.
Other EPROMs may supply other feedback rates.
7. The Current Controller Board gives signals
to the base driver boards to turn the output transistors
on and off, as determined by the encoder signals, by
the direction of rotation commanded, and controls the
PWM frequency according to the motor conditions.
POSSIBLE PROBLEM:
ENCODER LIGHT OR LIGHTS NOT CHANGING.
1. Check the power supply at TB1 terminals 8(+) and 7(-
). It should be 5.0VDC +/- 0.1VDC.
2. Check the signals at TB1 terminals 2, 3, and 4. The
proper signals are illustrated on page 8 of the Motor manual.
3. Change the Current Controller Board.
Figure 32: Layout of the Current Controller board
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