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can be used with some degree of confidence. By comparing several signals to each other, such
as gate drive signals, and obtaining similar readings, it can be concluded each of the waveforms
match one another and are therefore correct. Values are provided for using a digital voltmeter for
testing as well.
Pin
No.
Sche-
matic
Acro-
nym
Function
Description
Reading Using a Digital Voltmeter
1
IU1
Current sensed,
U phase, not con-
ditioned
Approx 400 mv RMS @100% load
.937 VACpeak @ 165% of CT current
rating. AC waveform @ output frequen-
cy of the adjustable frequency drive.
2
IV1
Current sensed,
V phase, not con-
ditioned
Approx 400 mv RMS @100% load
.937 VACpeak @ 165% of CT current
rating. AC waveform @ output frequen-
cy of the adjustable frequency drive.
3
IW1
Current sensed,
W phase, not con-
ditioned
Approx 400 mv RMS @100% load
.937 VACpeak @ 165% of CT current
rating. AC waveform @ output frequen-
cy of the adjustable frequency drive.
4
COM-
MON
Logic common
This common is for all signals.
5
AMBT
Ambient temp.
Used to control FAN high and low fan
speeds.
1 VDC approximately equal to 25C
6
FANO
Control Card sig-
nal
Signal from the control card to turn the
fans on and off.
0 VDC – ON command
5 VDC – OFF command
7
INRUSH Control Card sig-
nal
Signal from the control card to start gating
the SCR front end
3.3 VDC – SCRs disabled
0 VDC – SCRs enabled
8
RL1
Control Card sig-
nal
Signal from Control Card to provide status
of Relay 01
0 VDC – Relay active
0.7 VDC – inactive
9
Not used
10
Not used
11
VPOS
+18 VDC regula-
ted 16.5
to 19.5 VDC
The red LED indicates voltage is present
between VPOS and VNEG terminals.
+18 VDC regulated 16.5 to
19.5 VDC
12
VNEG
-18 VDC regulated
supply
-16.5 to 19.5 VDC
The red LED indicates voltage is present
between VPOS and VNEG terminals.
-18 VDC regulated supply
-16.5 to 19.5 VDC
13
DBGATE Brake IGBT gate
pulse train
Varies w/ brake duty cycle
Voltage drops to zero when brake is
turned off. Voltage increases to 4.04
VDC as brake duty cycle reaches max.
14
BRT_O
N
Brake IGBT 5V
logic level signal.
Varies w/ brake duty cycle
5.10 VDC level with the brake turned
off. Voltage decreases to zero as brake
duty cycle reaches max.
15
Not used
16
FAN_TS
T
Control signal for
fans
Indicates Fan Test switch is activated to
force the fans on high
+5VDC – disabled
0VDC – fans on high
High Power Service Manual for VLT
®
FC Series
Adjustable Frequency Drives
9 Special Test Equipment
MG.90.L1.22 - VLT
®
is a registered Danfoss trademark
9-3
9
Содержание VLT HVAC FC 100
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