Rockwell Automation 1395 Digital DC Drive FRN 5-10.10/9.30 - Manual (Page 26)

Chapter 2
Hardware Description
1 – 30 HP, 230VAC 2 – 60 HP, 460VAC
2-4
Surge Suppression – Surge suppressor MOV1 to MOV4 on the Power
Board protects the armature power bridge from line voltage spikes and line
surges.
Line Reactor – A reactor mounted outside the drive is used to protect the
power bridge SCRs from rapid rate of current changes (di/dt).
SCR Packaging – SCR packaging in the 1395 in bridge ratings 3.6 – 110A
(1 – 60 HP) consists of 2 SCRs per module. The regenerative construction
has 6 SCR blocks PM1 through PM6. The non regenerative construction
has 3 SCR blocks PM1, PM3 and PM5. Refer to Figure 2.3.
Pulse Transformers – Pulse Transformers on the Power Board provide
the gate firing pulses and voltage isolation for the armature SCRs.
Voltage Transient Protection – RC networks contained on the Power
Board are used to protect the SCRs against voltage transients (dv/dt).
DC Bus Snubbers – DC Bus Snubbers are used on 3.6 – 19 A units only.
DC Current Sensing – DC overcurrent sensing is provided using DC
transducer TD1.
Figure 2.3
Armature Bridge Components (OUTPUTS)
A1
PM1
To PSI/
Switcher
Board
3F
TD–1
L1 L2
G1
L3
G2
1F
4F
1R
4R
G2
G1
PM2
G1
G2
PM3 PM4
6F
PM5 PM6
G1
6R
3R
G2
G1
G2
5F
2F 2R
5R
G2
G1
A2
DB Resistor
M1
To Power
Board
To Power
Board
DB2
DB1
A1
A2
DC Contactor – Output of the armature bridge is connected to the DC
motor through the main DC contactor M1 (Fig. 2.3). Coil voltage to M1 is
controlled by contacts from the pilot relay K3 (on PSI/Switcher board) and
external 115VAC control input entering at TB2-2 and 3.
Bridge Output Connections – Bridge output connections labeled A1 and
A2 (Fig. 2.3) correspond to the NEMA standards for connection to the A1
and A2 leads of the DC motor. If dynamic braking is used, the dynamic
braking resistor bank is connected to terminals DB1 and DB2.