Electronic Control System
Integrated
Integrated
(700-
(700-
3
3
T
T
ALL)
ALL)
Series
Series
3-12
#3758412 - Revision B - December, 2006
Assist in Control of Variable Speed Compressor
s
(700TF/I-3 Only)
As mentioned on the previous page, temperature signals from the thermistors in the compartment are monitored by
the microprocessor and then displayed on the LCD.
When the compartment reaches high-offset (calling for cooling), an “ON” signal is sent from the control board to the
compressor’s inverter. The inverter (which is supplied with AC power at all times) then provide high DC voltage (3-
phase, 50 - 150 Hz), outputs to the compressor. The inverter in turn senses the compressor load. If the compressor
load is high, the speed command from the inverter will be for high speed compressor operation; if medium compres-
sor load, speed command from the inverter will be for medium speed; if low compressor load, speed command from
the inverter will be for low speed. If/when the compartment reaches low-offset, an “OFF” signal is sent to the invert-
er, which then cuts DC power to the compressor.
NOTE:
• The variable speed compressor, evaporator fan and the condenser fan will run a great majority of the time. This is
normal. These components will only cycle off during defrost and may also cycle off for short periods of time if the
ambient temperature is low enough.
• Initial speed command from an inverter to a compressor are always for High speed.
0
0
E2
E6
E10
E7
J5
J7
J3
J2
J1
J4
J6
J6
J5
J3
E2
E7
E10
E6
J2
J1
J7
J4
LOW VOLTAGE
HIGH VOLTAGE
CONDENSER
FAN MOTOR
NEUT
115 VOLTS
60 CYCLES
L1
FREEZER
FAN SWITCHES
FREEZER
FAN MOTOR
WHITE
BLACK
PURPLE
WHITE
PURPLE
RED
MEMBRANE SWITCH
DISPLAY
BLUE W/BLACK STRIPE
BLUE W/BLACK STRIPE
FRZ CAB
THERMISTOR
VSPEED
CONTROL
BOX
BROWN
BLACK
LT. BLUE
BLACK
M
M
PIN 1
PIN 1
PIN 1
0
PIN 1
0
0
0
PIN 1
PIN 1
PIN 1
0
Figure 3-21. 700TF/I-3 Signal Trace Schematic of Variable Speed Compressor Operation
IN EXCESS OF 200 VOLTS MAY
BE PRESENT AT INVERTER
AND COMPRESSOR!
1. Compartment
temperature
monitored by
microprocessor
3.
Inverter supplies
high DC voltage,
3-phase, 50 - 150
Hz signal, based
on compressor
load.
2. When cooling is called for,
115 Volts AC “ON” signal
supplied to compressor
inverter, evaporator fan
and condenser fan.
NOTE: Line voltage
supplied to inverter
at all times.