Common Problems And Solutions Of Epoxy Resin Cast Transformers

A dry-type epoxy resin cast transformer is a transformer in which the core and windings are not immersed in insulating oil. It is suitable for intermittent overload operation or emergency overload operation; due to the increase of load voltage and load voltage during overload, it is in a non-economic operation state, so continuous continuous overload operation should not be carried out.

Dry-type epoxy resin cast transformers need to understand the following issues during operation:

Is the insulation resistance of the core to ground low?

Mainly due to the high humidity of the ambient air, the insulation resistance of the transformer is reduced by the humidity.

Solution: Use an iodine tungsten lamp to bake continuously under the low voltage coil for 12 hours, including iron core, high and low voltage coil, as long as the insulation resistance decreases due to moisture, the insulation resistance value will be improved accordingly.

What is the reason for the zero insulation resistance of the core to ground?

Explain that the actual connection between the metals (may be due to burrs, wires, etc., is carried into the core by the paint, the ends overlap between the core and the clamp; the insulation of the feet is broken and the core is connected to the feet; there is a metal object falling off into the low voltage coil, causing the pull plate to connect to the iron core ;). Solution: Make it clear with a wire between the lead and the low voltage coil core level. After confirming that there are no foreign objects, check the insulation of the feet. If it still doesn't work. The following methods can be used: connect the grounding end of the electric welding machine to the grounding plate, and click the foot with a welding rod (the current is about 250A). The problem can only be solved once.

On-site power transmission should pay attention to those matters

Generally speaking, the power station generates electricity 5 times, and there are also 3 times. Before power transmission, check the tightening of bolts and metal foreign objects on the iron core; whether the insulation distance meets the power transmission standard; whether the electrical function is normal; whether the connection is correct; whether the insulation of each component meets the power transmission standard; There are loops (especially cable entry points) that allow small animals to enter; epoxy resin cast transformer

When power is affected, the shell and paved subway slabs are drained. What does it mean?

This indicates that the electrical conductivity between the shell (aluminum alloy) plates is not good enough and the grounding is poor.

Method: Break the insulation of the board with a 2500MΩ vibrator, or scrape the film at each joint of the shell and connect it to ground with copper wire.