Voltage Supply And Voltage; Imbalance; Starting The Unit; Test Modes - Trane Voyager Commercial Installation, Operation And Maintenance Manual

Voltage Supply and Voltage Imbalance
Supply Voltage
Electrical power to the unit must meet stringent
requirements for the unit to operate properly. Measure
each leg (phase-to-phase) of the power supply. Each
reading must fall within the utilization range stamped
on the unit nameplate. If any of the readings do not fall
within the proper tolerances, notify the power
company to correct this situation before operating the
unit.
Voltage Imbalance
Excessive voltage imbalance between phases in a three
phase system will cause motors to overheat and
eventually fail. The maximum allowable voltage
imbalance is 2%. Measure and record the voltage
between phases 1, 2, and 3 and calculate the amount of
imbalance as follows:
% Voltage Imbalance = [(AV – VD)/AV] x 100 where;
AV (Average Voltage) = (Volt 1 + Volt 2 + Volt 3) / 3
Volt 1, Volt 2, Volt 3 = Line Voltage Readings
VD = Line Voltage reading that deviates the farthest
from the average voltage.
E E x x a a m m p p l l e e : :
• If the voltage readings of the supply power
measured 221, 230, and 227, the average volts
would be: (221 + 230 + 227) / 3 = 226 Avg
• VD (reading farthest from average) = 221
• The percentage of imbalance equals: [(226–221) /
226] x 100 = 2.2%
The 2.2% imbalance in this example exceeds the
maximum allowable imbalance of 2.0%. This much
imbalance between phases can equal as much as a
20% current imbalance with a resulting increase in
motor winding temperatures that will decrease motor
life.
If the voltage imbalance at the job site is over 2%,
notify the proper agencies to correct the voltage
problem to within 2.0% before operating this
equipment.

Starting the Unit

Before closing the main power disconnect switch,
insure that the "System" selection switch is in the
"Off" position and the "Fan" selection switch for
Constant Volume or SZ VAV units is in the "Auto"
position.
Close the main power disconnect switch and the unit
mounted disconnect switch, if applicable.
RT-SVX34R-EN
W W A A R R N N I I N N G G
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t t h h e e s s e e t t a a s s k k s s . .
HIGH VOLTAGE IS PRESENT AT TERMINAL BLOCK
HTB1 OR UNIT DISCONNECT SWITCH.
Upon power initialization, the RTRM performs self-
diagnostic checks to insure that all internal controls are
functional. It also checks the configuration parameters
against the components connected to the system. The
LED located on the RTRM module is turned "On"
within one second of power-up if internal operation is
okay. The economizer dampers are driven open for 5
seconds then fully closed (if applicable).
When an economizer is installed DO NOT ENTER the
TEST mode until all calibration startup functions have
been completed. Otherwise, the economizer actuator
and power exhaust output may not function properly
during any of the test mode steps. Allow 2 minutes
after unit power up to complete economizer calibration
before entering the test mode function. Use the
following "Test" procedure to bypass some time
delays and to start the unit at the control panel. Each
step of unit operation can be activated individually by
temporarily shorting across the "Test" terminals for
two to three seconds. The LED located on the RTRM
module will blink when the test mode has been
initiated. The unit can be left in any "Test" step for up
to one hour before it will automatically terminate, or it
can be terminated by opening the main power
disconnect switch. Once the test mode has been
terminated, the LED will glow continuously and the unit
will revert to the "System" control, i.e. zone
temperature for constant volume units or discharge air
temperature for variable air volume units.

Test Modes

There are three methods in which the "Test" mode can
be cycled at LTB1-Test 1 and LTB1-Test 2.
N N o o t t e e : : For Constant Volume or Variable Air Volume test
steps, test modes, and step resistance values to
cycle the various components, refer to
Table 46, p. 74.
Step Test Mode
This method initiates the different components of the
unit, one at a time, by temporarily shorting across the
two test terminals for two to three seconds.
For the initial startup of either a Constant Volume or
Variable Air Volume (Single Zone or Traditional) unit,
S S t t a a r r t t u u p p
, p. 68 -
67