Modine Manufacturing DBS Installation And Service Manual page 33

COMPONENT DESCRIPTIONS
(40) Motor Starter – (OPT)
The motor starter is factory installed in the blower electrical
section. A motor starter is required for:
• All three phase motors
• Single phase motors 1-1/2 Hp and greater
If the factory installed motor starter option was not ordered with
a unit that requires it, a motor starter must be field supplied and
installed. Alternatively for three phase motors, see also the
Variable Frequency Drive option below.
The overload module of the motor starter is designed to protect
the motor from exceeding the nameplate amps. If the motor
exceeds the amp draw on the current set point dial, the trip
condition is indicated by a red color in the trip indicator window.
The current set point dial is factory set to the motor full load
amps listed on the motor nameplate.
The motor starter can be placed in the automatic or manual
reset positions. Automatic reset is accomplished by depressing
the "RESET" button and turning the button 1/4 turn. When in
the automatic reset position, if the overload module trips, the
module will reset itself once the overload relay has cooled.
In the manual reset position, if the overload module trips, the
"RESET" button must be depressed before the blower can
operate.
The contactor module includes one (1) normally open auxiliary
contact. The contact rating is 10 amps.
Motor Starter
CONTACTOR
MODULE
CURRENT
SET POINT
DIAL
OVERLOAD
MODULE
(40) Variable Frequency Drive – (OPT)
The VFD controller adjusts the motor rpm to vary the unit air
flow. The minimum air flow may be varied between 30 and
100% of the full speed air flow depending on the controls
selection of the unit (refer to the section "Variable Air Volume
Applications" on page 25 for additional information).
The control changeover options include two speed, building
pressure control, and building management control. For units
with the Modine Control System option (Model Digit 12=9),
additional control options may be available. Refer to the latest
revision of the Modine Control System Manual, literature 74-510
for additional information.
A1 A2
1 L1 3 L2 5 L3 13 NO
TRIP
INDICATOR
WINDOW
RESET
2 4 6 14
T1 T2 T3 NO
A2
A R
H
E
S
E
T
NO
NC
98 97 95 96
2 4 6
T1 T2 T3
(41) Mild Temperature Stat - (OPT) (All Except Digit 12=9)
The mild temperature thermostat is designed to lockout the
burner during mild weather conditions which prevents the
burner from cycling. The thermostat must be field set to the
desired mild temperature condition. Refer to the latest revision
of Modine publication 75-540, "Installation/Setup Instructions,
Electronic Mild Temperature Thermostat" for additional
instructions.
For units with the Modine Control System option (Model Digit
12=9), this feature is integral to the control logic and utilizes
existing sensors included with that option. Refer to the latest
revision of the Modine Control System Manual, literature 74-510
for additional information.
(42) Proportional Temperature Controller – (OPT) (All
Except Digit 12=9)
A proportional temperature controller is provided with Air Control
options GG or GH (Digits 20 & 21) and factory installed in
the electrical section. The controller compares the mixed air
temperature set point and the mixed air temperature from the
Proportional Temperature Controller Sensor. The controller
sends a 2-10 Vdc signal to the modulating damper actuator
in order to maintain the set point. The controller includes a
set point dial that must be field set to the desired mixed air
temperature (typically 55°F). This acts as a dry bulb economizer,
primarily by utilizing warmer outside air as first stage heating to
minimize gas heat energy usage.
Proportional Temperature Controller
For units with the Modine Control System option (Model Digit
12=9), when the damper control is dry economizer, Model Digits
20-21 will always be GA and the control will be integral to the
Modine Control System control logic. Refer to the latest revision
of the Modine Control System Manual, literature 74-510 for
additional information.
(43) Warm-Up Stat – (OPT)
A warm-up stat can be provided with Air Control options EA,
GG, or GH (Digits 20 & 21) and factory installed in the electrical
section with the sensor in the return air stream. The warm-
up thermostat monitors the return air temperature to the unit
and prevents the fresh air dampers from opening until the
temperature of the return air has reached the desired set point
(typically 65°F or 5°F below the room temperature).
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