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3.5.8 CIRCUIT BREAKER CURRENT RATING SETTING (SSR ONLY)
Purpose: The
CIRCUIT BREAKER CURRENT RATING setting helps prevent in-rush induced nuisance
tripping of the circuit breaker immediately upstream of the controller. The
HTC evaluates the
square of the current related to time (I
2
T) and adjusts the output duty cycle accordingly, limiting
the amount of current to an acceptable level.
Range: 0.3 to 100.0 amps
(
CURRENT TURNS RATIO = 1.00)
Procedure: Adjust the CIRCUIT BREAKER CURRENT RATING setting to the heating circuit breaker
size (i.e. 30.0 amps). Note that the
CIRCUIT BREAKER CURRENT RATING setting is affected by the
CURRENT TURNS RATIO setting. The absolute maximum adjusted CIRCUIT BREAKER CURRENT RAT-
ING
setting is 300.0 amps. The absolute minimum adjusted CIRCUIT BREAKER CURRENT RATING
setting is 0.1 amps. See section 3.5.22 on page 26 for more information regarding the
CURRENT
TURNS RATIO
function.
Note: This feature should not be used to reduce the size of a circuit breaker or increase the max-
imum heating cable length. It can be quite effective in preventing nuisance trips due to incorrect
design or factors outside those considered by the design.
3.5.9 MAXIMUM POWER SETTING (SSR ONLY)
Purpose: This user-selectable level limits the maximum amount of power applied to a heat trace
circuit. This is an average power calculated by the controller using the average current and
applied voltage. The
HTC switches the output on and off rapidly to limit the average current to an
appropriate level. The
MAXIMUM POWER level may be adjusted to eliminate step-down transform-
ers, lower the effective output wattage of a cable, or implement energy management of the heat
trace circuit.
Range: 3 to 33,000 Watts
(
VOLTAGE and CURRENT TURNS RATIOS = 1.00)
Procedure: Adjust the MAXIMUM POWER level to the desired value (watts). Use the TEST TRACING
function to observe the power limiting operation.
Notes:
• This function may be set within reasonable limits for the particular tracer being powered. The
effective resolution of the setting is limited to 1/30th of the calculated full on power.
• Do not set the
MAXIMUM POWER below full output for applications that do not require control
of power.
• This feature is affected by the
VOLTAGE and CURRENT TURNS RATIO settings. The maximum
range using adjusted values of voltage and current is 65,535 watts. See sections 3.5.21 on
page 26 and 3.5.22 on page 26 for more information regarding the turns ratio functions.
3.5.10 3-PHASE POWER CALCULATION (V3.11 AND UP)
Purpose: This parameter selects the type of power calculation that the HTC is to perform.
Setting:
NO or YES
Procedure: If an automatic 3-phase power calculation is desired, select YES. If a normal power
calculation is desired, select
NO.
Note: For the total 3-phase power calculation to be accurate the following conditions must be
met:
• All three phases must be balanced and star (“Y”) connected
• The measured corrected current is one of the phase currents
• The measured corrected voltage is the line to line voltage
The formula used to calculate this total power is: P
total
= √3 x I
phase
x V
line-line
3.5.11 TS FAIL MODE (V3.11 AND UP)
Purpose: This parameter determines whether the
HTC turns the output switch ON or OFF if all
selected temperature sensors fail to provide a control temperature.
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