JPS6013202Y2 - Electric car grounding circuit - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a grounding circuit for supplying the feeder current of an electric vehicle and the fault current of the drive motor.

FIG. 1 is a diagram schematically showing a grounding circuit for feeding current of an electric vehicle.

In this Figure 1, 1 is an overhead wire, 2 is a pantograph, and 3
is an electrical equipment mounted on an electric vehicle, 4 is a current grounding wire, 5 is a grounding brush, 6 is an axle, 7 is a wheel, 8 is a rail, and the current flows as shown by the arrow in the figure: overhead line 1 → pantograph 2 → electrical equipment 3 → Current grounding wire 4 → Grounding brush 5 → Axle 6 → Wheel 7 →
Flows like rail 8.

Figure 2 is a diagram showing the main parts of a conventional electric car grounding circuit, in which 9 is the electric car drive motor, 10 is the drive motor grounding wire, and 11
1 is a truck, and 12 is a journal bearing.

Otherwise, 4 to 6 are the same as those in FIG. In such a conventional circuit, the drive motor ground line 10 is connected at one end to the drive motor 9 and at the other end to the ground brush 5 (feeding current ground line 4), as shown in the figure.
When a flash fault occurs for some reason, the fault current is grounded immediately, and the fault current is provided to prevent electrolytic corrosion of the bearing caused by passing through the bearing of the journal bearing section 12 and being grounded. It is something.

However, in such a conventional circuit, the drive motor grounding line 10 is connected to short-circuit the current grounding line 4 and the drive motor 9 as clearly shown in FIG. 3, so that the broken line in FIG. As shown, feed current grounding wire 4→
The circuit of grounding brush 5 -> drive motor grounding wire 10 -> drive motor 9 - bogie 11 -> gear bearing 12 -> wheel 7 -> rail 8 is severely affected.

Therefore, when the grounding brush 5 is lifted off the axle 6 due to vibration, a current flows through the circuit, causing electrolytic corrosion to occur in the bearing of the journal bearing portion 12.

The object of this invention is to provide a grounding circuit for an electric vehicle that eliminates the above-mentioned conventional drawbacks by inserting a backflow blocking diode in the drive motor grounding line.

An embodiment of this invention will be described below with reference to FIG.

Fig. 4 is a simplified diagram showing the main parts of one embodiment of the grounding circuit for an electric car according to this invention, in which 4 is the current grounding wire of the electric car, 5 is the grounding brush, 6 is the axle, and 9 is the electric car. The vehicle drive motor 10 is a drive motor ground wire 13 for grounding fault current of the drive motor 9, which has one end connected to the drive motor 9 and the other end connected to the current ground wire 4 (ground brush 5).
is a backflow blocking diode inserted into this drive motor grounding line 10.

In this case, the backflow blocking diode 13 is connected to the drive motor 9.
The grounding brush 5 is connected to the drive motor 9 side with a polarity that conducts electricity, but does not conduct electricity from the grounding brush 5 to the drive motor 9 side.

Next, the operation of this devised circuit will be explained.

That is, if the drive motor 9 causes a flashover accident for some reason, the fault current flows from the drive motor 9 to the drive motor grounding wire 10 (backflow blocking diode 13) to the grounding brush 5 to the axle 6, as follows. As shown in Figure 1, the flow flows from wheels 7 to rails 8.

Therefore, the above fault current does not flow through the bearing of the journal bearing portion 12, and electrolytic corrosion thereof is prevented.

Furthermore, when the grounding brush 5 is lifted off the axle 6, the reverse current blocking diode 13 prevents the feed current from flowing into the drive motor 9 side, and in the conventional circuit, the feed current does not flow into the drive motor 9 side. Electrolytic corrosion of the bearing of the journal bearing portion 12 caused by this is prevented.

As described above, according to this invention, since the backflow blocking diode 13 is inserted into the drive motor grounding wire 10, the journal will not only be damaged in the event of a flash fault of the drive motor 9, but also when the grounding brush 5 is lifted off the axle 6. No current flows through the bearing of the bearing portion 12, which has the effect of preventing electrolytic corrosion of this bearing.

[Brief explanation of the drawing]

Figure 1 is a diagram schematically showing the grounding circuit for the current of an electric car.
Figure 2 is a diagram showing the main parts of a conventional electric car grounding circuit, Figure 3 is a simplified diagram of the main parts of the same grounding circuit, and Figure 4 is an example of an electric car grounding circuit according to this invention. FIG. 4... Current grounding wire, 9... Electric vehicle drive motor, 10... Drive motor grounding wire, 13.
...Reverse flow blocking diode. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] In a grounding circuit for an electric vehicle, the grounding circuit for an electric vehicle is equipped with a drive motor grounding wire that connects the electric vehicle drive motor and a grounding brush that is connected to the electric vehicle's current grounding wire and attached in contact with the axle. A backflow blocking diode is connected in series between the grounding brush and the electric vehicle, so that when the grounding brush is lifted off the axle, the electrical current of the electric car is prevented from flowing back to the drive motor. Car ground circuit.