DE187761C - - Google Patents

Description

IMPERIAL

PATENT OFFICE.

PATENT LETTERING

- JV * 187761 - CLASS 21 c. GROUP

Self-starter for direct current electric motors.

Patented in the German Empire on March 23, 1906.

The subject of the invention is a self-starter for direct current electric motors. The drawing shows the circuit diagram of the idle starter. A is the power line to which the anchor circuit. C of the electric motor D can be connected by means of the switch B and the current connection pieces c ¹ , c ² . In the armature circuit C , the starting resistors W ¹ , W ² , W ³ and W ¹ and a maximum current relay E are switched on. The armature e ^{1 of} the relay E is provided with two current connection pieces e ² and e ³ , which are isolated from one another and from the armature. A Hebei F, which is under the action of a spring G of adjustable tension, seeks ^{to hold the armature e 1 of} the relay in the position shown in the drawing, in which the current connector e ³ a parallel to the starting resistors circuit H by connecting the Current connection pieces h ^{3 und.c 3 connected} to the armature circuit. ^{With the armature e 1} in this position, the motor is therefore briefly connected to the mains.

J is the actual starting relay. The armature f ^{1 of} this relay carries a current connection piece i ² , which when the armature moves one after the other with the current ^{connection pieces μ 1} , u ² , u ³ , u * and M ^{5 of} the starting resistors, ie can short-circuit the individual resistance levels one after the other. The armature P carrying an extension piece i ⁸ is guided straight by rollers K and can be braked in its movement by a thumb f ^{l of} the lever F. In the circuit M of the starting relay, which is connected to the current connection pieces c ¹ and c ^{2 of} the armature circuit, two current ^{connection pieces m 2} and e ^{2 are} switched on, one of which (e ² ), as mentioned above, with the armature e ^{1 of} the Maximum current relay is connected. The current connection piece wz ² is set up and arranged in such a way that when the circuit is closed, the current connection piece e ² can experience a small displacement without ^{coming out of contact with the current connection piece m 2} (spring, immersion or sliding contact). In the position of the armature e ^{1 shown in} the drawing, the current connection pieces m ² and e ^{2 are} out of contact, the circuit M is therefore open. If the armature circuit C connected through the switch B to the power line, the current passes from the current tailpieces c ¹ by the turns of the maximum current relay E to the Slromschlußstücke c ^3, from here, h through the current circuit pieces e ^{3 3,} lines H and the armature of the motor D to the current connection pieces c ² back. The motor is connected to the mains without a starting resistor. As a result of the lack of a counter electromotive force in the motor, the amperage in the armature circuit rises immediately after the motor is switched on. As soon as the current strength has risen to the level permitted for starting the motor, ie so far that the magnetic force acting on the armature e ^{1 of} the relay E is able to overcome the resistance of the lever F under the action of the spring G, is the armature e ^{1 of} the relay E against the action of the spring G

dressed. This first disconnects line H from armature circuits C, so that all of the current must flow through the starting resistors. Furthermore, the thumb f ^{l of} the lever F is pressed against the extension piece i ^{3 of} the armature z ' ^{1 of} the starting relay /, as a result of which it is prevented from moving. At the same time the current connection pieces e ² , m ^{2 come} into contact

ίο with each other and close the circuit M of the starter relay. 'This exerts a pull on its armature i ¹ which, however, is initially not strong enough to overcome the braking force of the lever F '.

In the meantime the engine has started moving. With increasing number of revolutions the counter electromotive force of the motor increases, while at the same time the strength of the current in the armature circuits decreases. The train-

ao by virtue of the maximum current relay E and, accordingly, the braking force of the lever F decrease. The circuit M , however, remains closed despite the decrease in the current strength, since, as explained above, the current connection piece e ² can experience a small displacement without coming out of contact ^{with the current connection piece m 2.} The displacement of the armature e ¹ is practically zero here, since as soon as the tensile force of the maximum relay E drops to the value of the opposing tensile force of the spring G , the bearing pressure or. the friction between the thumb f ¹ and the extension piece i ³ becomes zero. At a certain level of friction, the tensile force predominates. of the starter relay J the braking action of the lever F, the armature i ¹ begins to move and switches the first stage W ^{1 of} the starter. Resistance briefly. The amperage in armature circuits C increases immediately. This game is repeated until all starting resistors are short-circuited and the motor has reached its normal number of revolutions. Since the current intensity has dropped to the operating current intensity and a new current surge no longer occurs, the pressure exerted by the lever F on the armature e ¹ under the action of the spring G outweighs the tensile force of the maximum current relay and brings the current connector e ^{3 of} the armature in contact with the current connectors A ³ and c ³ , whereby the circuit H is connected to the armature circuit C. At the same time, the circuit M of the starting relay is interrupted by removing the current connection piece e ² from the current connection piece m ² , and the thumb / ^{1 of} the lever F lifts off the armature i ¹ . As a result, it falls into its original position shown in the drawing.

From now on the current has the same course as immediately after switching on of the motor.

The starter described above has the advantage that the starting current can be chosen arbitrarily high and regulated by changing the tension of the spring G. can be. In addition, the starter protects the engine against overloading without it how the lead fuses cause a malfunction in the event of an overload. Because as soon as the current intensity, which increases as a result of the overload of the motor, exceeds the amount of the starting current intensity reached, the maximum current relay is activated again and switches the starting resistor in front of the armature of the Engine. The starter relay is switched on at the same time. After eliminating the overload the number of revolutions of the motor is set by short-circuiting in the manner described above the resistances automatically returned to the normal level.

Since the starting relay is de-energized after the start-up and the maximum current relay, offers only a low resistance, the starter consumes little energy and is therefore also advantageous from an economic point of view.

Claims (2)

Patent Claims: .1. Self-starter for direct current electric motors, characterized in that a maximum current relay (EJ ■ ) is switched on in the armature circuit (C) of the electric motor, the armature (e ¹ ) of which connects the winding of the actual starting relay (J) to the power line (A) when the motor is switched on , alternately brakes and releases the armature (i \) of the starting relay according to the current surges that arise in the armature circuits as a result of the switching on of the motor and the short-circuiting of the resistance stages and, after the start-up is complete, the winding of the starting relay disconnects from the power line. 2. Embodiment of the self-starter according to claim 1, characterized by a circuit (H) running parallel to the starting resistor (W ¹ to W ⁴ ) , which is passed through the armature (e ¹ ) of the maximum current relay immediately after the motor is switched on by the armature circuits (C) '' the engine is switched off and switched on again after starting. 1 sheet of drawings.