SU141196A1 - Relay device for the protection of propulsion systems with electric drive in a generator-engine system - Google Patents

Description

The invention relates to electrical protective devices that provide reliable protection against damage to the electric drive of the propeller shaft during shock overloads.

The existing electrical circuits of protection against overloads of electric drives of rowing units operating on the generator-motor system are based on the introduction at the time of the overload of additional ballast resistance into the excitation circuit of the generator exciter.

The introduction of ballast resistance entails a decrease in the voltage on the core of the exciter, and therefore a decrease in the voltage on the generator and the limitation of the current in the generator-motor circuit.

This scheme, being an effective means for limiting propellers of a rowing drive, which are of a sufficiently long nature, cannot provide reliable protection during short-term but frequent shock overloads, for example, when an icebreaker is operating in ice.

This is due to two reasons, firstly, the high magnetic inertia of the excitation windings and, consequently, the relatively slow decay of the field of excitation and, secondly, due to insufficient limits of variation of the excitation current when the ballast resistance is on and off (the maximum ratio is up to 1 : 2).

As a result, the current in the main generator-motor circuit (with shock overloads) has time to reach a value sufficient to turn off the main automata earlier than the current is limited by the inclusion of ballast resistance in the exciter excitation circuit.

In order to achieve a more efficient operation of the overload protection system of the electric drive, the inventors have proposed two schemes.

The first scheme provides for the complete rupture of the exciter excitation circuit instead of introducing ballast resistance, the second one

No. 141196-2 not only breaks the excitation circuit of the exciter, but also switches its opposite polarity (in order to even more quickly extinguish the field of excitation). In both cases, an electromagnetic relay is selected as an overloading element. parallel to the winding of the additional poles (or compensatory winding) of the propeller motor.

The contacts of this relay either break the excitation winding circuit (according to the first scheme), or reverse the winding power supply (according to the Bth scheme).

FIG. 1 shows a protection circuit with an open circuit of the exciter winding circuit.

FIG. 2 shows a circuit with a rupture and subsequent reversal of the power supply of the circuit of the same winding.

The field / generator winding 2 (Fng. 1), connected south with the propeller motor 3, is powered by driver 4.

In parallel with the winding of the additional poles 5 of the generator 2, the coil 6 of the electromagnetic overload relay is connected.

The normally closed contacts 7 and 5 of this relay are connected in series with the excitation winding 9 of the driver 4, which has an independent power source.

Parallel to the excitation winding 9, the discharge resistance / 0 is turned on. The scheme works as follows.

At the moment of occurrence of shock overload of the propeller motor 3, the current flowing through the winding of the additional poles 5 increases rapidly, and the voltage drop in this winding increases with it. Upon reaching a certain value of the voltage drop, the coil 6 of the electromagnetic relay attracts the core and opens normally closed contacts 7 and 5, which will cause the excitation of the exciter circuit and, consequently, a rapid decrease in the current in the main circuit.

The second circuit (Fig. 2) differs from the first one by the presence of additional two normally open contacts // and 12, which are turned on immediately after disconnecting contacts 7 and 5 and reporting the reverse polarity of the supply circuit of excitation winding 9 of the exciter 4. Reversing the supply of excitation allows forcing the fall excitation of the generator and, therefore, further accelerate the reduction of the current in the main circuit of the generator-motor

1. A relay device to protect electric motorized propeller systems using a generator-motor system that excites a generator from a separate exciter, the circuit of which includes contacts of an electromagnetic relay that operates during an engine overload, characterized in that, in order to increase the effectiveness of protection, These contacts are included in the controlled circuit in series without shunting resistance, i.e. they completely break this circuit.

2. A device according to c: 1, characterized in that the relay contacts form a reversible quadrupole to change the polarity of the voltage applied to the excitation winding of the exciter.