DE1018529B - Feed system for supplying direct current to a load circuit, especially for the power supply of automatic telephone exchanges - Google Patents

Description

GERMAN

The invention relates to backup DC power supply equipment in the form of emergency batteries, in particular for automatic telephone exchanges or -amtar. ·

It is sometimes necessary to have a device that normally supplies direct current to a load circuit, such as B. an AC rectifier with a reserve voltage source, e.g. B. an emergency battery to be provided, intermittently from the rectifier or is charged "drop by drop" via a circuit that contains a half-wave rectifier, which is so> polarized that the charging current through the Half-wave rectifier in the direction of the high Resistance, flows. The battery that is in series with the half-wave rectifier is parallel to the Output terminals of the main rectifier or another main feed jellyfish on the load circuit connected, with a suitably high resistance connected in parallel to the Halbweggleidiriahter. the The output voltage of the main equilibrium becomes so is chosen to be higher than that of the reserve battery, so that the main rectifier usually has the takes over the entire load, d. H. the. Consumers supplied with electricity and also the emergency battery intermittently or "drop by drop", whereby the battery is prevented from being fed into the load circuit feed because the half-wave rectifier is under voltage is in the blocking direction. If the main rectifier fails, the voltage drops the load below that of the battery, and the latter takes over the feeding accordingly Load circle.

However, it is sometimes necessary that the emergency .strombattarie can withstand a discharge for two hours without the voltage of the battery falling below a certain permissible value. Such a condition requires the use of a backup battery of a higher voltage than the normal load voltage, and the charging relay described above for intermittent or "drip-wise" charging must be modified, otherwise the half-wave rectifier will no longer fail. Voltage load is in the reverse direction and current a, us of the battery flows into the load circuit, even if the main rectifier is working properly. One method of overcoming this disadvantage is known to be that the battery z. B. divided into two sections by tapping, -of which the ■ main section has a voltage that is slightly below the normal load voltage. This section is connected in series with a half-wave rectifier to the load circuit in parallel with the main rectifier in the manner described above; switched. The smaller one; Section of the battery that is out · sufficient

Feed system for feeding
Direct current to a load circuit,
especially for the power supply
of automatic telephone exchanges

Applicant:

Westinghouse Brake & Signal Company Limited, London

Representative: Dr. E. Wiegand, Munich 27,
and Dipl.-Ing. W. Niemann, Hamburg 1, Ballindamm 26, patent attorneys

Claimed priority:
Great Britain 8 July 1952

Alec Hervey Bennet Walker, London,
has been named as the inventor

Lines consists of the voltage of the sanitary battery on the. required to bring to value is in series with the first mentioned large, section of the battery connected to the, load circuit, if dia HaiUptstromqueille fails. .. "

Usually, while, are the main peers The load feeds the two sections of the battery in series with one another through a series connected Main rectifier and auxiliary rectifier charged intermittently or "dropwise", with the auxiliary rectifier provides the required extra voltage that is added to the voltage of the main rectifier must be used to charge the entire battery.

The use of such a system as described above includes the use of the backup battery as a means of smoothing the output DC current, as is usual with the usual The system is the case in which the battery and the main control unit are parallel to the load circuit are switched: and. both at the feeding of the load take part. Therefore other means of smoothing had to be found. This is special important if the system feeds an automatic telephone exchange or a telephone call.

In accordance with the invention, a system is described above. Type with one ... or more smoothing levels. to smooth the output current of the main supply source of which each stage has an inductive

709 758/165

Tire impedance and a capacitor, the capacitor being the output stage in parallel with the half-wave rectifier is switched. The circuit of the Emdstuifenkonidensators doing this has two beneficial effects. First, it enables size of the capacitor to be reduced extremely sharply because it can withstand the full load voltage instead of - to have to, just the tension of the smaller one Section of the battery needs to withstand, and

19 b to the positive terminal 20 through the rectifier 17 in the direction of the lowest resistance (forward direction) flows. The contact 18 is opened to me when the entire battery is to be charged to its full extent. The positive terminal of the Batterieiabschnittes 19 a is with the positive! Terminal 20 of the load circuit connected by a circuit, which is usually an open! Contact 16 is interrupted, but closes,

Second, it helps prevent the io from dropping when the AC power is off. Load voltage in. The period between the In the output circuit of the auxiliary rectifier 14 is

Moment at which the AC power supply fails, and the moment the entire battery comes on. the load is switched to prevent.

The invention is hereinafter referred to. Hand of the drawing, for example, explained in more detail, where the

a two-stage smoothing circuit connected, the first of which Stage is composed of an inductive impedance 21 and a capacitor 23 and its second stage (output stage) an inductive impedance 22 and a capacitor 24 contains. This capacitor is designed to reduce the ripple that

Figure in, schetnatic form an emergency power system would otherwise occur in the load circuit and. the),

illustrated according to the invention. especially if, the load from · an automatic

According to the drawing, a Netztrarosformator 3 20 telephone exchange or the like. Is very undesirable

a primary winding 2 connected to. Input terminals. 1 can. The capacitor 23 is in the usual way

for connection to an alternating current source (not parallel to the positive and negative output

shown) is connected, and three secondary lines are connected. The capacitor 24 is, however

windings 4th, 5 and. 6. The secondary winding 6 does not feed in this way, but rather it is

a main rectifier 15, the output rectifier 25 of which is connected in parallel to the half-wave rectifier 17,

current to a load circuit (not shown) when the capacitor 24 in; usually in parallel

led, the ¹ would be connected to the output terminals 20 to the output lines, it would have to

closed is. In parallel to the output terminals, 20 is to withstand the full voltage of the load and

also connected an emergency battery 19, the two would have to have correspondingly large dimensions.

Sections 19a and 19 &, of which the ab- 30 By being parallel to the rectifier 17

section 19 b of the 22 cells and the section 19 α of 4 cells. The secondary winding 5 of the transformer 3 is connected to the alternating electronics terminals of a first auxiliary rectifier 14 in series with the Impe-

is switched, in which case it is effective in the same way, is the maximum voltage which it has to endure, that of the batterk section 19a, and it can therefore be very considerable in size

rectifier 15, which is in series with the auxiliary rectifier 14 lies, the load circuit, and the voltage 'on the

round winding 10 of a saturable. Throttle or 35 reduced.

Inductance coil from. appropriate form connected, the operation of the system is the following ©:

in the illustrated case by a control winding 9. Under normal conditions, the main feed is controlled by the same, which is controlled by a discriminator and
Amplifier 12 in accordance with the voltage
on the one on the output terminals. 20 connected 40 load is held at approximately 50 V, the load circuit is fed with direct current. This regulation by controlling the auxiliary DC auxiliary rectifier 14 is automatically connected in series with the main converter 14 in accordance with the rectifier 15, so that the two span fluctuations of the load take place. At the same time, add up. It can be seen that the main rectifier 15, which is in series with changes in the load voltage to the corresponding 45 of the auxiliary rectifier 13, changes an lead to the output voltage of the main whole battery. The battery voltage is added to rectifier 15, so that the voltage is kept close to 2.2 V per ZdIe. It can be seen that the load is kept essentially constant in both cases, as long as the AC power supply remains in operation, the load voltage and the battery. This voltage is kept at about 50 V voltage, at the associated auxiliary rectifier, so that, as these two auxiliary rectifiers

The secondary winding 4 of the transformer 3 are independent of each other, fluctuations, in the output a second. Auxiliary rectifier 13 via the output current of one does not affect the other. Impedanzwicldung 8 bucket second, saturable: Choke 55 Under these conditions, the voltage of the inductance coil or with a control winding 1, the battery section 19 b, at 2.2 V per cell, 48.4 V and, from a discriminator and amplifier 11 in over - Since the load voltage is kept at 50 V, in accordance with the voltage on the battery 19, the rectifier 17 is supplied under voltage direct current, the arrangement loading in the Spemchtung so * that the battery is made such that the battery is usually prevented from adding current to the load circuit at 60

constant intermittent drop-wise charging at a voltage of approximately 2.2 V per cell, ie 48.4 V at section 19 b and 8.8 V at section 19 ″, is maintained. Between the junction of the two sections of the battery and the positive terminal 20 of the load circuit, a normally closed contact 18 and a half-wave rectifier 17 are connected in series, the polarity of which is such that it will be described below. The capacitor 24 is charged to a voltage which is equal to the difference between the load voltage and the voltage of the battery section 19b .

If the main power supply fails, the output current of the rectifiers 14 and 15 falls to zero, and the load is then fed from the emergency battery, with the transition from one supply source to the other taking place automatically. There is

the conditions current from the battery section 70 an unavoidable delay between, the time

point of failure of the main power supply and the closing of contact 16 to switch the full battery to the load. If the capacitor 24 were not connected in parallel with the rectifier 17, the voltage at the consumer would have to drop to a value below 48.4 V before the battery can take over the supply. , Characterized in that the smoothing capacitor 24 is connected in parallel with the Halbweggleichrichter 17 in the final stage of Hauptstromzufuhir adds to the failure of the voltage auif which exploding capacitor is charged, to that of the Batterieabschnitteis 19 b and contributes to the voltage across the load on their to hold the full value of 50 "V until the whole battery is activated, closing the contact. 16.

When it is desired to charge the battery to the full extent, the output current of the auxiliary rectifier 13 is adjusted to cause this increase and the battery to a voltage of. approximately 2.75 V per cell is charged. The voltage at the battery section 19 b increases accordingly to approximately 60.5 V, and since this voltage is higher than the load voltage, the battery would supply current to the consumer. To prevent this, the contact 18, which is usually closed is open when the battery is to be charged to its full extent.

It will be apparent that the invention does not apply to the particular embodiment shown in the drawing is limited. For example, the two auxiliary rectifiers 13 and 14 can be from separate power sources instead of. the winding in 4 and. 5, which are provided on the main transformer 3, fed be, or it can optionally be the two auxiliary rectifiers from a power source and the Main rectifier 15 can be fed from another source. It can also be the arrangement of the saturable. Chokes, which control the supply of the auxiliary rectifiers, have any suitable form. For example, although it is shown as a single coil in the drawing, the winding can consist of a Be composed of a plurality of coils, which are connected in any suitable manner, and it If desired, self-excitation and feedback effects can also be included.

It will also be seen that, although the invention has been applied to a backup or emergency power system has been described, at dean the load voltage and the intermittent, or "Dropwise" charging of the battery is regulated in a special way, the invention is not limited to such an arrangement. It can also be seen that the main rectifier is a May be multiphase rectifier connected to single or multiphase auxiliary rectifiers.

Claims (1)

PATENT CLAIM: Feed system for supplying direct current to a load circuit, in particular for the power supply of automatic telephone exchanges or the like, with a main DC power supply and a reserve battery (Noitstrombatterie), the is divided into a first, large and a second, small section, of which the first battery part has a normal voltage slightly below that of the main feeder and in series via a half-wave rectifier to the load circuit and usually from the main source via your half-wave rectifier in the direction of its high resistance is charged intermittently and the second The battery section consists of a sufficient number of cells to carry the voltage across the bring the entire battery to a predetermined value which is higher than that of the main supply source, with means for switching on which can be activated automatically in the event of a main supply failure of the second battery section in series with the first battery section to the load circuit and one for smoothing the output current of the main supply source. Smoothing circle with one or more stages, each of which consists of an inductive impedance and a capacitor is composed, characterized in that the capacitor is parallel to the output stage is connected to the half-wave rectifier. Considered publications:
German patent specification No. 683 580. 1 sheet of drawings © 70i 758/165 10.57