Parallel System and LBS System Installation
Liebert
®
APM
™
42
4.2.8 Key Interlock System
Figure 27 Key interlock system control wiring
Transfer Parallel Liebert APM Units to System Bypass Mode
1. Verify that all Liebert APM units are in internal maintenance bypass mode. The light in the
SKRU push button will turn On when all units are in bypass.
2. Hold the push button in and rotate the key in K0 to remove key.
3. Insert key in MBB interlock K1 and rotate to withdraw interlock. Key will remain in interlock.
4. Close the MBB.
5. Open the MIB and rotate thekey in K2 to extend interlock.
6. Remove key from MIB interlock K2 and place in K0.
7. Rotate key in K0 to lock key.
Return Parallel Liebert APM Units to Normal Mode
1. Verify that all Liebert APM units are in internal maintenance bypass mode. The light in the
SKRU push button will turn On when all units are in bypass.
2. Hold the push button in and rotate the key in K0 to remove the key.
3. Insert the key in the MIB interlock and rotate the the key in K2 to withdraw interlock.
4. Close the MIB.
5. Open the MBB and rotate the key in K1 to extend interlock.
6. Remove the key from the MBB interlock K1 and place it in K0.
7. Rotate the key in K0 to lock the key.
UAM0180E
Rev. 0
Buyout Liebert APM Paralleling Switchboard
Notes
1. See drawings UAM01080A, UAM01080B,
UAM01080C, UAM01080D and UAM01080F.
2. MBB auxiliary switch connections are on the normally
closed and common positions.
3. MOBs auxiliary switch connections are on the normally
open and common positions.
4. Contact closes when UPS is on internal bypass.
Field-Supplied Wiring
Liebert APM Bypass Module
Only One Shown
UHRF3S67X2 (J5, J12)
Liebert
APM #2
*See Note 4
J5
TB3
TB2
TB3
TB2
AC Output
MOB1
MBB
MIB
MOB2
See Note 3
See Note 2
See Note 3
AC Input
1
2
1
2
1
2
3
3
4
3
4
4
3
4
X2 J12
X2 J5
X2 J12
X2 J5
1
2
3
4
3
4
Ø A
Ø B
Ø C
Liebert
APM #1
*See Note 4
ØA
Ø C
Ø B
Neu
SKRU
KO
Inner Door SWBRD
2 Fuses
2A
Push
Button
Kirk Key
K2
Kirk Key
K1
5
6
