BCD.00617 Rev AB,16-Nov-2015

Page 5 of 15

MELCHER

The Power Partners.

Accessories Data Sheet

Backplanes BPD, BPF for T Series

3-phase (

∆∆∆∆∆) Configuration

With special back plane version BPF 1037 (

∆-configuration)

for LT units exclusively

Low mains 120/208 VAC

The input section of the 3 LT units is wired in a

∆-connection

enabling full output power of the LT units at low mains input

voltage 120/208 VAC.

Back planes in 3-phase (

∆) configuration are available on

request. Modifications to the back plane in the field from "Y" to

∆-configuration (and vice versa) are not recommended.

Maximum nominal input voltage: 230 VAC + 10%, phase to

phase. Higher input voltages may damage the LTs as well as

the back plane. Connection to the mains should strictly be

done according to fig.: 3-phase (

∆) configuration. Wrong

connection at the input may damage the LT converters as well

as the back plane. An external fuse needs to be installed into

each input line.

Fig. 6

3-phase (

∆ ) configuration, L1, L2, L3

120/208 VAC (e.g. USA) LT models only.

Not applicable for UT models.

Output Section

Power Bus

The back plane is fitted with a generously dimensioned bus

bar system. Each bus bar (4 mm thick Aluminum alloy profile,

identified with its polarity) is fitted with 2 captive nuts (M 6)

serving as connection points to the load as well as to the

battery system. Depending upon the application either the

positive or the negative pole of the battery may be earthed.

For application specific requirements such as reduced ripple

current, reduced low frequency ripple voltage, enhan-ced

hold-up time or heavy pulse loads, the back planes are

available with additional output capacitors (see table: Type

Sur vey). The output capacitors are mounted between the

positive and the negative bus rails.

Front- End Version

To provide maximum system reliability especially with n+1 re-

dundant systems, each positive output path is fitted with a

decoupling diode mounted onto the positive bus rail. The

diodes D11, D21, and D31 prevent a possible Power Down on

the power bus in the case of a short-circuit across the output of

one of the T units. To maintain the signalling functions of the

T unit(s) in the case of a single inhibit or a single mains phase

failure, a PTC in parallel to the decoupling diode allows a

small reverse current from the DC bus supplying the control

functions of the affected T unit.

Battery Charger Version

Direct battery charging or powering battery buffered systems

require an adequate float charge voltage over the specified

temperature range. Decoupling diodes should be avoided

due to their voltage drop, affecting the float charge voltage of

the battery. To maintain system redundancy adequatedly rated

fuses (F11, F21 and F31, rated F20A minimum, 250 V, 6.3 – 32

mm each) are mounted in each positive output line. In the

case of a short circuit across the output of one of the T units

the relevant fuse will blow, interrupting the reverse short circuit

current supplied by the battery and the remaining T units.

Power Down Signal (D1, D2, D3)

The power down signal monitors the voltage level of the bus

bar system. Depending upon the application it may be advan-

tageous to use the power down signal D1 and D2 in a

redundant configuration and the third signal (D3) as a

separate warning signal at a higher threshold level. For such

a configuration the jumpers of X3 should be set in the posi-

tions

ΣD - D1 and ΣD - D2. (See fig. Jumper strip (X3), Signal

meshing.)

For individual adjustment of the power down level see also:

System Integration.

Inhibit

The output of a T unit may be enabled or disabled by the inhibit

input signal. Moreover the output voltage can be controlled

with an external temperature sensor connected to this input. If

just the inhibit function is used, the units can be individually

inhibited. If the output voltage is temperature controlled the

same sensor signal should control all units in the rack and the

jumpers of X3 should be set in all 3 inhibit positions,

Σi – i1,

Σi – i2, and Σi – i3 (See fig. Jumper strip (X3), Signal meshing).

System Good Signal (Sys In 1, 2, 3/Sys Out 1, 2, 3)

The System Good signal can be used either for status moni-

toring of each individual T unit or as a combined signal for

status monitoring of the whole system. For overall system

status monitoring jumpers should be set in the positions Si1-

So2, Si2 – So3 (See fig. Jumper strip (X3), Signal meshing).

The System Good input of the first T unit in a system (T3)

should be referenced to the negative output. This can be done

either on the jumper strip X3 with a jumper in position

⊥-Si3

(See fig. Jumper strip (X3), Signal meshing.) or directly at the

terminal strip X5, by connecting Sys In 3 to Vo–. (See also:

System Integration.)

L1

LT

3

X1

L1

L2

L3

N

LT

2

LT

1

L2

L3

04020

∆

∆

∆