Generac
®
Power Systems, Inc. 29
4.2 Check to see if the set screw is tightened
securely, but do not over tighten. This screw
should be set to 2 to 4 inch pounds.
5. Check for any wire damage along the entire run
between the E Panel and the sender.
5.1 Check for any areas along the wire with miss-
ing insulation. This could allow the 523 line
to momentarily come into contact with
ground causing a false shut down.
5.2 Check to see if the wire is pinched anywhere
along the run. A wire that is pinched between
the sheet metal can cause the 523 wire to
momentarily come into ground causing a false
shut down. A pinched wire may also cause the
wire to break inside the insulation, this could
cause the 523 line to momentarily "open"
while running. This will also result in a false
shut down.
Check the OTS mounting
The ground return (0) connection for the OTS is
made by the physical connection of the sender to the
engine block. This connection may be made directly,
or through a series of adapters or fittings.
Check for the following at each junction point:
1. Check for a tight mechanical connection.
2. Check for a good electrical connection.
Resistance measurements
Power down the E Panel by removing the front panel
fuse.
Remove CON2 from the back of the E Panel.
1. Measure the resistance between the OTS stud and
the 523 wire inside the control panel. If this meas-
urement is greater than 2-3 Ohms, replace the
entire wire running between the control panel and
the OTS stud.
2. Measure the resistance between the body of the
sender and the 0 location on the control panel ter-
minal strip. If this measurement is greater than 2
-3 Ohms, go back and carefully check the OTS
mounting and the star ground connections on the
engine block.
AC VOLTAGE DISPLAY
The E Panel monitors the generator's AC output volt-
age. This voltage can be viewed locally on the E
Panel's display, or remotely using Genlink.
There are two user programmable set points for the
Generator output voltage: over voltage and under
voltage. Both parameters are active after the hold off
timer has expired. They can be programmed to be a
status message, non-latched alarm, latched alarm, or
shut down alarm.
The voltage displayed on the E Panel, and the
over/under voltage set points are all based on the gen-
erators full line to line output voltage. However, in
most cases full line to line voltage is not connected to
the E Panel. (Please refer to the unit's wiring diagram
and schematic for complete wiring details.)
The E Panel has a programmable voltage scaling fac-
tor that is used to scale the sensing voltage applied to
CON4-4 and CON4-6. This allows the E Panel to dis-
play full line to line voltage.
The scaling factor should be checked if the E Panel is
not displaying the line to line voltage correctly.
Check the scaling factor against the generators set up
sheet. If the set up sheet is not available, contact
Generac's service department for the recommended
setting.
The voltage scaling factor can also be used to "cali-
brate" the voltage display.
Example:
A 480 volt unit has 240 volts sensing voltage applied
to E Panel CON4-4 and CON4-6.
The E Panels scaling factor should be set to 2.0 to
provide a proper line to line display voltage.
If, however, the E Panel displays 490 volts with a scal-
ing factor of 2.0, the scale factor may be adjusted
slightly to "calibrate" the voltage display. In this case,
the displayed voltage is roughly 2% high, so the scal-
ing factor should be reduced by 2% to 1.96. Change
the scaling factor and recheck the voltage display. If
necessary, readjust the scaling factor until the voltage
display is properly "calibrated".
Please note the following:
1. Software versions V1.07 and earlier had a one
decimal point scale factor.
Software versions V1.08 and later have a two dec-
imal point scale factor.
2. The E Panel displayed voltage is not used in any
way to regulate the generators output voltage. The
voltage regulator is responsible for regulating gen-
erator voltage.
RPM SENSOR AND ENGINE SPEED
ALARMS
(Refer to Figures 3.5, 3.6 & 3.7)
OVERVIEW
The E Panel uses an RPM sensor to monitor engine
speed. The RPM sensor is mounted in the blower
housing and positioned so the tip of the sensor is
directly above the engine flywheel teeth. As the fly-
wheel rotates, the sensor will send an electrical pulse
to the E Panel each time a tooth passes the sensor.
The E Panel will count these pulses and convert them
into engine speed.
Section 3 — Troubleshooting and Diagnosis
E Option Control Panels
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