Motor control loop power supply mode

Abstract

The invention provides a motor control loop power supply mode. According to the motor control loop power supply mode, a special control transformer is arranged at the wire outlet of a two-way power conversion switch inside a feed cabinet, wherein the two-way power conversion switch is connected to two power sources, one power source is the common bus of an existing motor control cabinet, the other power source is an emergency power supply device such as a diesel generator, and when the first power source stops working, the emergency power supply device can be put into service instantly to further ensure emergency power supply of type I and II motor loads. Together with a main loop, the special control transformer achieves power switch control and is always powered by one power source. Therefore, the motor control loop power supply mode is applicable to various grounding systems, effectively solves the problem of fluctuation of control power sources, ensures reliability of the power sources of the control transformer and further ensures reliability of a motor control loop power source of an entire system.

Description

technical field [0001] The invention relates to the technical field of low-voltage power distribution, in particular to a power supply mode for a motor control loop. Background technique [0002] In the low-voltage grounding system, when the grounding system is a TN system, one point of the power supply end is directly grounded (usually the neutral point), and the exposed conductive part of the electrical device is connected to this grounding point through a protective neutral conductor or a protective conductor. According to the combination of the neutral conductor and the protective conductor, the TN system has two situations: the TN-S system and the TN-C system, such as figure 1 , figure 2 shown. The TN system can directly provide N-phase, and then provide AC220V control power. However, not all places are suitable for TN systems. For places with high requirements for uninterrupted power supply and strict restrictions on ground fault voltage, IT grounding systems are s...

AI Technical Summary

Problems solved by technology

[0004] Table 1 Disadvantages of the two motor control loop power supply methods

[0005] Motor control circuit power supply mode: shortcoming: Directly from the common bus It cannot be used in the IT grounding system, and the control power is prone to fluctuations Add a control transformer in the receiving cabinet Unable to provide stable control power for Class I and Class II motor loads

[0009] However, the power supply mode of the traditional control loop cannot meet the power supply needs of the first and second loads in the grounding system. The control loop of the traditional IT system cannot meet the switching of the backup security power supply because the control transformer is installed in the power receiving cabinet. In the IT grounding system, when the control circuit loses power, even if the main circuit of the motor has been put into the backup power supply, the motor still cannot run, which seriously affects the safe operation of the equipment

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