Danfoss VLT HVAC FC 100, Service Manual, Page: 185 / 220

Pin
No.
Sche-
matic
Acro-
nym
Function Description Reading Using a Digital Voltmeter
17 FAN_ON Pulse train to gate
SCR’s for fan volt-
age control. In
sync with line freq.
7 trigger pulses at 3Khz
5VDC - fans off
18
HI_LOW Control signal
from Power Card
Signal to switch fan speeds between high
and low
+5VDC = fans on high,
Otherwise, 0VDC.
19 SCR_DI
S
Control signal for
SCR front end
Indicates SCR front end is enabled or dis-
abled.
0.6 to 0.8 VDC – SCRs enabled
0VDC – SCR disabled
20 INV_DI
S
Control signal
from Power Card
Disables IGBT gate voltages 5VDC – inverter disabled
0VDC – inverter enabled
21 Not used
22 UINVEX Bus Voltage scaled
down
Signal proportional to UDC OV switch must be off
- 1 VDC = 450 VDC [T4/T5]
- 1 VDC = 610 VDC [T7]
23 VDD +24 VDC power
supply
Yellow LED indicates voltage is present. +24 VDC regulated supply
+23 to 25 VDC
24 VCC +5.0 VDC regula-
ted supply.
+4.75-5.25 VDC
The green LED indicates voltage is
present.
+5.0 VDC regulated 4.75 to
5.25 VDC
25 GUP_T IGBT gate signal,
buffered, U phase,
positive. Signal
originates on the
control card.
2v/div 100us/div Run@10Hz
2.2–2.5 VDC
Equal on all phases
TP25-TP30
26 GUN_T IGBT gate signal,
buffered, U phase,
negative. Signal
originates on the
control card.
2v/div 100us/div Run@10Hz
2.2–2.5 VDC
Equal on all phases
TP25-TP30
27 GVP_T IGBT gate signal,
buffered, V phase,
positive. Signal
originates on the
control card.
2v/div 100us/div Run@10Hz
2.2–2.5 VDC
Equal on all phases
TP25-TP30
28 GVN_T IGBT gate signal,
buffered, V phase,
negative. Signal
originates on the
control card.
2v/div 100us/div Run@10Hz
2.2–2.5 VDC
Equal on all phases
TP25-TP30
29 GWP_T IGBT gate signal,
buffered, W
phase, positive.
Signal originates
on the control
card.
2v/div 100us/div Run@10Hz
2.2–2.5 VDC
Equal on all phases
TP25-TP30
30 GWN_T IGBT gate signal,
buffered, W
phase, negative.
Signal originates
on the control
card.
2v/div 100us/div Run@10Hz
2.2–2.5 VDC
Equal on all phases TP25-TP30
9 Special Test Equipment
High Power Service Manual for VLT
®
FC Series
Adjustable Frequency Drives
9-4
MG.90.L1.22 - VLT ® is a registered Danfoss trademark
9