IQ DP-4000
SECTION 5 - PROGRAMMING THE IQ DP-4000
TD 17548B
31
Figure 5.1 Overvoltage Detection and Reset Levels
Example 1
A system has the following settings:
Nominal AC Line Voltage = 208 V
Overvoltage Detection Level = 125%
Reset Threshold = 75%
For this system an overvoltage alarm will occur at:
208V x 125% = 260V
The overvoltage alarm will reset at:
260V - 75% x (260V - 208V)
= 260V - 75% x (52V)
= 260V - 39V = 221V
In this example, the overvoltage alarm will not reset
until the system voltage is below 221V.
Example 2
A system has the following settings:
Nominal AC Line Voltage = 480 V
Overvoltage Detection Level = 110%
To determine the Reset Threshold setting for the
overvoltage alarm to reset below 504 V:
The overvoltage alarm will occur at
480V x 110% = 528 V
504V = 528V - RST% x (528V - 480V)
504V = 528V - RST% x (48V)
RST% x (48V) = 528V - 504V = 24V
RST% = 24V / 48V = 0.50
In this case, set the reset threshold to 50%
5.12.15.2 Undervoltage Reset Threshold
To determine where to reset an undervoltage alarm,
find the voltage where the undervoltage alarm occurs.
This voltage is the nominal AC line voltage (see Section
5.5 p.23) multiplied by the undervoltage detection level
(see Section 5.12.13 p.29).
The reset voltage is a percentage of the difference (0 to
100%) between the nominal Voltage and the
undervoltage detection level, as determined by the
reset threshold. Compute this by:
UVR = UVDL+ RST x (NOM - UVDL)
where
UVR = Undervoltage Reset (Volts)
UVDL = Undervoltage Detection Level (Volts)
RST = Reset Threshold
NOM = Nominal AC line Voltage (Volts)
On the following page, Figure 5.2 illustrates the
undervoltage detection and reset levels.
Overvoltage Reset
Zone for Reset
Threshold = 50%
Overvoltage Trip Zone
Reset Threshold = 0%
Reset Threshold - 0 to 100%
Reset Threshold = 100%
Overvoltage Detection Level (Volts)
Reset Threshold = 50%
Nominal Line-to-Line Voltage (Volts)
Overvoltage Reset
Zone for Reset
Threshold = 100%
Summary of Contents for Cutler-Hammer IQ DP-4000
Page 2: ......
