CIRCUITS FOR HEATING STORAGE BATTERIES

CIRCUITS DE CHAUFFAGE POUR ACCUMULATEURS

English Abstract

ABSTRACT OF THE DISCLOSURE
A battery heating circuit comprising a transformer
having a primary winding for connection to an a.c. supply and a
secondary winding, and at least two pairs of batteries. The
two batteries of each pair are connected in series and the series
combinations of the pairs of batteries are connected in parallel
between d.c. terminals. The secondary winding is connected
between the common terminals of each pair of batteries.

Claims

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A battery heating circuit comprising a transformer
having a primary winding for connection to an a.c. supply and a
secondary winding, and at least two pairs of batteries, the two
batteries of each pair being connected in series and the series
combinations of the pairs of batteries being connected in
parallel between d.c terminals, the secondary winding being
connected between the common terminals of each pair of batteries.
2. A circuit as claimed in claim 1 in which the
transformer is a single phase transformer.
3. A circuit as claimed in claim 1 in which the
transformer is a polyphase transformer having its secondary
windings connected in delta configuration, there being as many
pairs of said batteries as there are phases of the supply.

Description

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This invention relates to circuits for heating storage
batteries to enable charging to be carried out in low temperature
conditions. The invention is particularly concerned with
circuits for heating several batteries simultaneously.
In accordance with the present invention a battery
heating circuit comprises a transformer ha~ing a primary winding
for connection to an a.c. supply and a secondary winding, and at
least two pairs of batteries, the two batteries of each pair
beiny connected in series and the series combinations of the
pairs of batteries being connected in parallel between d.c.
terminals, the secondary winding being connected between the
common terminals of each pair of batteries.
~n the accompany:ing drawings Figures 1 antl 2 are
circu:it d:i.acJram.s of two d:if;eerent examples oE thc invent:i.on.
Referring firstly to Figure 1 the circuit includes
four batteries 10, 11, 12 and 13 connected in series parallel
arrangement across the d.c. terminals 14, 15 of the circuit.
The batteries 10 and 11 are in series with one another as are
the batteries 12, 13.
The heating circuit makes use of a transformer 16
having a single primary 16a and a single secondary 16b. The
pr.imary 16a is connected to an a.c. supply ]7 and th~ secondary
16b has one end connected to the interconnecti.on of the ba-tteries
10, 11 and the other end connected to the interconnection of
the batteries 12, 13.
With this circuit heating current from the transformer
secondary 16b passes through the four batteries, but the direct
current drawn from the batteries does not pass through the
secondary 16b.
Turniny now to figure 2 a similar arrangement is show
for heating six batteries 110, 111, 112, 113, 1:l~ ancl 115 from
a 3 phase a.c. supply 117. As in Figure 1 the batteries are



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connected in a series parallel arrangement with the batteries
connected in series in pairs between the d.c. terminals 118,
119. The transformer 116, in this case, is a 3 phase transformer
with each of its primary and secondary windings 116a, 116b delta
connected. The three terminals of the secondary winding 116b
are connected respectively to the interconnections of the
three pairs of batteries.
Once again direct current does not pass through the
secondary windiny 116b.
Either or both of the primary and secondary windings
of the transformer 116 may alternatively be star connected.




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