bonitron M3460, Руководство для пользователей

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D_M3460_D_CMAN_vall_00a 4/17/2020
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4.8. DC B
US
T
HRESHOLD
V
OLTAGE
S
ETTING
The DC bus threshold voltage is the voltage at which the M3460 maintains the DC bus
during a power quality event. Whenever the output DC bus voltage drops below the
DC bus threshold voltage setting, the M3460 becomes active to regulate the DC bus
to the setpoint voltage.
The DC bus threshold voltage is important to the installation in that if it is set too low,
the attached drive may trip on an undervoltage fault. If it is set too high, then minor
power disturbances, such as line notching or high harmonics that would not normally
cause the drive to have problems may cause the M3460 to become active when there
is no need. If this is a constant or frequent occurrence, the M3460 may overheat and
not be available in the event of an actual sag or outage.
The M3460 DC bus threshold voltage setting is determined by the drive installation.
Consult the manufacturers' specifications on the attached drive, and make sure that
the DC bus threshold voltage is above this value. For instance, many 460-480VAC
input drives have an undervoltage trip point of 400VDC. This may allow the drive to
keep operating, but the DC bus voltage may not be enough to allow the drive to operate
at full power. Therefore, it's useful to set the DC bus threshold voltage setting above
this value.
Generally, the DC bus threshold voltage should be set at 10% below the nominal DC
bus level. Use the following formula to calculate this value:
Vdc = Vac ∗ √2 ∗ 0.9
An actual on-site check may be performed to determine the loaded DC bus level as
well as the amount of ripple present on the DC bus.
If you find that your incoming AC power is susceptible to long term sags or conditions
below 10%, the M3460 may become active when not needed. In this case, the DC bus
threshold voltage setting should be lowered to allow the M3460 to only be active during
a true power quality event. The M3460 should not become active during normal
operation.
The DC bus threshold voltage is factory preset on all M3460 modules according to
Table 6-2 of this manual. However, field adjustment of this setting may be required to
achieve the optimum setpoint level for any given system. There are two ways to
determine the DC bus threshold voltage described below. Be sure to read through both
methods completely before attempting any adjustment of the DC bus threshold voltage
setting.
D A N G E R
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I G H V O L T A G E S W I T H R E S P E C T T O C H A S S I S A R E P R E S E N T
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E V E R U S E A N U N I N S U L A T E D T O O L O F A N Y K I N D
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F A I L U R E T O H E E D T H E S E W A R N I N G S M A Y R E S U L T
I N S E R I O U S I N J U R Y O R D E A T H !