Contactor control

Contactor control in the frame above the traction motor on an end frame of the E 91.3

The contactor control was used for the control of various types of AC motors or to control the resistance control of DC motors applied with great performance. With increasing performance they prevail, especially for controlling electric locomotives . It has been in use since around 1910. For your control were contactors of different design and construction, which was then in the vernacular also hops were called, used. From the 1930s on, contactor control was replaced by cam switches with or without fine adjusters, depending on the type of tensile forces to be expected, which guaranteed less maintenance, a longer service life and finer control.

description

Schematic representation of a contactor control with locking

Contactor control was one of the many ways of controlling different voltages of DC motors and AC motors in electric locomotives. The contactor control was developed because the ES 1, which was equipped with a single-phase series motor in the first electric locomotive, the difficult-to-control mechanical gears of the rotary transformer were too cumbersome to operate and difficult to operate due to their weight. The approach was similar with DC motors. The various types of control emerged in competition between all renowned electrotechnical companies and contactor control was the numerically dominant type of control of electric locomotives. And if you are very lucky today, you can still experience one or two museum pieces of electric locomotives with this control ( E 69 02 , E 95 or E 77 ) in operation.

Contactor control of an E 91.3 with triple polarized choke coil and double tap on the secondary winding of the transformer

The purpose of the control was to change the power of the electric motors by changing the supplied voltage to a greater or lesser extent to control the taps on the secondary side of the power transformer . She controlled the high-voltage circuits of the vehicles with contactors. The contactors were controlled from the driver's cab either with safe extra-low voltage or with compressed air, depending on the type of contactor and the company carrying out the work. The circuit is described using the example of the control of the single-phase series motor; the switching process between two taps of the transformer had to take place without interruption, because overvoltages had to be avoided by opening contactors . For each two adjacent contactors worked together with the involvement of the sketch with D designated choke coil . This gave the motor the arithmetic mean value of the voltages of the two taps. When switching to a higher speed level, the low contactor had to be closed first and then the next higher one switched on. When shifting down, this shifting process was carried out in reverse. Since the contactors of the even numbers and those of the odd numbers each have the same access to the choke coil D , simultaneous switching on of odd or even contactors must be avoided in any case, as this would cause a short circuit . For this purpose, the contactors are provided with a locking contact, which should prevent two contactors with the same straightness from being switched on. The shifting process took place in the driver's cab to such an extent that a control lamp lit up when the driver's cab was upshifted; when the next gear was reached, it went out again. This also explains the simple control of the contactor control; Switching the drive switch to the highest speed level did not result in a voltage jump to this level; the locking contacts gradually switched the locomotive to the desired level.

This circuit was the general approach to contactor control. If larger tensile loads were to be controlled, they made do with more taps on the transformer and one more lines to the choke coil. In our example, the E 91.3, there were two transformers, which provided security against a transformer defect, and this locomotive also had three lines to the choke coil. This enabled three contactors to be switched on at the same time. The drive motors to be controlled were connected in series. They had a switch-off control to switch off a defective electric motor. Locomotives with only one transformer had the option of double tapping on the secondary side, which also allowed the number of taps to be increased, as was the case with the E 71.1 . A drop in the control voltage resulted in an immediate shutdown of all contactors; the operator can then only re-establish the contactor control using the travel switch position 0 .

application

Contactor controls were preferably used in electric locomotives for various services and showed good results until control with cam switches and fine adjusters came along . In the beginning, they were also much easier to operate compared to operation with a rotary transformer or a control with brush adjustment as with the repulsion motor . Its application was particularly necessary in locomotives with several electric motors, and so the first locomotives with multiple motor drives, such as the E 71.1, were also equipped with it. There are no deficiencies in the relevant locomotives listed in the literature. Certain shortcomings such as the still low number of speed steps and sticking were initially overlooked , the locomotives were manned by two men at the time and the loads to be transported were limited due to the short distances. Locomotives with single axle drive required contactor control.

With the E 95 , a borderline case had arisen in the use of contactor control with regard to the tractive forces to be controlled and the production costs. When the vehicles with cam switches and fine adjusters came up, the attitude of the locomotive staff changed, as they were able to make much more precise switching possible. Then when the switch came up to one-man operation that meant for the locomotives contactor controlled the off . Unless they were retrofitted, they were retired.

Manufacturer

The manufacturers of contactor controls included the companies AEG , Siemens-Schuckertwerke (SSW) and Bergmann Electricitäts-Werke (BEW).

literature

B. Wachsmuth The controls of the electric alternating current main line locomotive of the Prussian State Railways in Electric Rail Vehicles on Glaser's Annalen 1909-1929 , Transpress-Reprint, Berlin 1990, ISBN 3-925952-11-X , page 54 ff.

H. Tetzlaff Electric railcars for catenary operation in electric rail vehicles on Glaser's Annalen 1930-1953 , Transpress-Reprint, Berlin 1990, ISBN 3-344-00477-8 , page 79 ff.

H. Tetzlaff Five Years of German Electric Locomotive Construction in Electric Rail Vehicles on Glaser's Annalen 1930-1953 , Transpress-Reprint, Berlin 1990, ISBN 3-344-00477-8 , page 165 ff.

Web links

Individual evidence

^ B. Wachsmuth: The controls of the electric alternating current main line locomotive of the Prussian state railway. In: Electric rail vehicles on Glaser's annals 1909-1929. Transpress-Reprint, Berlin 1990, ISBN 3-925952-11-X , page 54 ff.
^ H. Tetzlaff: Five years of German electrical locomotive construction. In: Electric rail vehicles on Glaser's annals 1930-1953. Transpress-Reprint, Berlin 1990, ISBN 3-344-00477-8 , page 165 ff.
↑ Glanert / Borbe / Richter Reichsbahn-Elloks in Schlesien VGB-Verlag 2015, ISBN 978-3-8375-1509-1 , page 233

[1] B. Wachsmuth: The controls of the electric alternating current main line locomotive of the Prussian state railway. In: Electric rail vehicles on Glaser's annals 1909-1929. Transpress-Reprint, Berlin 1990, ISBN 3-925952-11-X , page 54 ff.

[2] H. Tetzlaff: Five years of German electrical locomotive construction. In: Electric rail vehicles on Glaser's annals 1930-1953. Transpress-Reprint, Berlin 1990, ISBN 3-344-00477-8 , page 165 ff.

[Glanert_Seite_233-3] Glanert / Borbe / Richter Reichsbahn-Elloks in Schlesien VGB-Verlag 2015, ISBN 978-3-8375-1509-1 , page 233