Limiting Output By automatically reducing the current to alternators field
coil, the output current of the generator can be limited. During a current limiting
condition (similar to all power supplies) the output voltage will automatically drop. The
Model 710 regulator senses the alternator output current through an external shunt, or
hall effect type current sensor.
The advantage of current limited
output instead of using a circuit breaker (with or without a shunt trip) for current
control in installations which incorporate a battery in parallel with the load is the
ability to provide continuous power output without overheating the alternator or engine,
and without disrupting the power output. A battery with a damaged cell or in a low state
of charge will cause the breaker to trip; the current limit feature of the Model 710 will
continue to supply power.
Overload Warning Alarm This alarm signal can be set either before or after the
alternator reaches the current limit set point. This adjustable set point is independent
of the current limit set point. The standard signal output is designed to drive a LED
light on a remote panel; with minor interface other types of devices can be controlled
with this signal such as a secondary generator, shunt trip breaker, relays, etc.
temperature Protection Overtemperature Protection The voltage regulator has a temperature
sensing circuit which will automatically reduce the current to the field coil should the
alternator overheat. This will help protect the genset should cooling to the alternator
fail or if a short develops inside the alternator. During over temperature condition the
operator is signaled via a LED light. The advantage of this feature is to provide
continued power (diminished level) under an adverse condition.
Automatic Engine Speed Control
Automatic Engine Speed Control Polar Powers voltage
regulator can drive a one-step solenoid actuating the engines throttle in response to the
current demand placed on the genset. This two-speed throttle control will save
considerable fuel and extend engine life. During low current demand, the engine can
operate at low speed and still supply the required regulated voltage. When the current
demand reaches an adjustable set point, the engine solenoid is energized, increasing
engine speed. There is a manual override which forces the generator to stay in the high
Precision Output Voltage Regulation
Precision Output Voltage Regulation The Model 710
incorporates a pulse-width-modulated, DC to DC, linear regulator to provide a proportional
voltage output to the field coil. The circuit is fast and responsive to load fluctuations
on the genset output. A separate input is provided for voltage sense in order to reduce
the effects of voltage drop and load noise across the power transmission line.
Enable Switch The Model 710 can be switched on and off
remotely. When connected to a thermostat, mounted on the engine for example, the genset
output can be automatically and efficiently brought on line after the engine has warmed
up. The feature also prevents battery drain into the field coil during the off state.
Remote Console Capability
Remote Console Capability There is a provision on board
which allows connection to a remote display or system controller via on-board connector
- Voltage adjust
- Regulator on/off (enable)
- Engine speed override (forces the solenoid to stay energized)
- Over current warning
- Over temperature warning
The Model 710 can be custom configured to meet each application
requirement. The Model 710 is available in all voltages from 12 to 48 Vdc, and field coil
currents up to 20 amps.
Board only, 4.5" X 4.5" X 1" inches (114.3 X 114.3 X
Calibration will require an experienced
electro/mechanical technician with the proper equipment.
- Setting the load dump (overvoltage clamp) will require the operator to do
- Select the voltage clamping point.
- Determine the minimum resistive load required to clamp the voltage. An
insufficient load will fail to clamp the voltage and too large a load will cause the
circuit to oscillate.
- Since the transients are fast, an oscilloscope is required to observed
events and calibrate.
- Potentiometer (Pot) R-34 is adjusted clockwise to increase the voltage
- Output current limit, Pot R-12, is adjusted clockwise to increase the
- Over current alarm, Pot R-15 is independent of R-12. Turn clockwise to
increase the alarm set point.
- Pot R-50 is adjusted clockwise to increase the current (limit) before the
regulator switches the engine to a higher speed. To prevent the engine from oscillating
between low and high speed there is a current differential between switch to high and
switch to low.
- Pot R-25 is used to adjust the output voltage.
- Switch S1 (if installed on the circuit board) is used to switch the
voltage adjustment between the remote panel pot and pot R-25.
Remote Panel Connector J1, MIL-C-26482, 10 pin. Pin
assignments are based on whether the connector is mounted from the component side or the
circuit side of the circuit board. The following pin assignments are correct when the
connector is mounted on the circuit side:
|Voltage adjust pot
|Voltage adjust wiper
|Voltage adjust pot
|Common for enable and speed
|Overtemperature LED cathode
|Overtemperature LED anode
|Overcurrent LED cathode
|Overcurrent LED anode
|Sensor Input Connector, Sub D, 9 Pin.
|Current shunt, output side
|Current shunt, alternator side
|Load dump transistor, gate
|Load dump transistor, Kelvin
|Second load dump transistor, gate
|Positive voltage sense
|Terminal Block, 6 Circuit
|Positive output to field coil
|Positive output to speed solenoid
|Negative output to field coil
|Negative output to speed solenoid