Littelfuse T7900 Series - Manual

Generator Control
© 2013 Littelfuse Protection Relays & Controls
Basic
www.littelfuse.com/t7900
T7900 SerieS
Electronic Potentiometer
Ordering numBer
TerminalS
11-12
1-3
T7900.0010 24 Vdc/Vac
T7900.0030 250 Vac
Description
The T7900 Electronic Potentiometer is used as converter
between pulse contacts and a device requiring control
adjustment by a voltage or current signal, such as an
electronic speed controller. The T7900 acts in a similar
manner to a motorized potentiometer, except that the
outputs are a voltage, a current or a pulse width modulated
signal (PWM), while the motorized potentiometer has a
variable resistor output.
In generator control applications, the T7900 can be used
together with a Synchronizer and a Load Sharer. The T7900
converts the increase and decrease pulses of these modules
into a suitable analog voltage, current or PWM signal. This
analog output signal can be used as a control input to the
electronic speed controller.
Ordering Information
Simplified Circuit Diagram
Features & Benefits
Specifications
Supply 8-36 Vdc/Vac
Consumption Max. 120 mA at 24 Vdc
Output Ranges –10 V-+10 V (or any part of this, e.g. 0 V-+1 V)
0-20 mA (or any part this, e.g. 4 mA-20 mA)
0-100% PWM 500 Hz (or any part of this e.g. 10-90%)
0-100% PWM 2.94 MHz (or any part of this
e.g. 10%- 90%)
PWM Output Signal Frequency: 500 Hz of 2,94 KHz. Level: 0-10 V
Default reference: 50%
Operating
Temperature –20°C to +70°C
EMC EN50263
Burn-in 50 hours before final test
Enclosure Material Polycarbonate. Flame retardant
Weight 0.3 kg for T7900-00, 0.5 kg for other types
Dimensions H 70 mm (2.7“); W 100 mm (3.9“);
D 115 mm (4.5“)
Installation 35 mm DIN rail or 4 mm ( 3 / 16 ”) screws
SUPPLY
24 Vdc/Vac RESET REF
POWER REF.
IN1 IN2 IN3 INCR REF DEC
+ –
T7900
(Electronic Potentiometer)
L
1
L
2
Optional
AC Supply
0-10 V REF
±10 V 0-20 mA PWM
FeaTureS BeneFiTS
Wide selection of output
ranges including PWM
Ensures possible use with a broad variety of
speed governors and voltage regulators
Independent ramp-up &
ramp-down time setting
Provides optimum controlabilty of speed
governors and voltage regulators regardless of
generator size
Power reference function
Enables alternative use as power reference
unit providing generator load set point in grid
parallel installations
Available with Vac supply Enables direct supply from installation
Visual indication of
increase/decrease signals
Provides quick and concise status information
DIN-rail or screw-
mount & adjustment by
potentiometers
Easy installation
Rev: 4-A-050313