Why MT control unit, some no display?

1, if the current is reduced to 0.2 * In (In = rated current) below the digital display disappears. To ensure that more than 20% in order to ensure that 20% may be displayed may not be displayed.

2, if still below the 0.2 times the rated current, this is meaningless.

3, the control unit display, only the reference, the control unit is to provide the protection for the MT.

4, some for the site will be lit this panel will not light up, the control unit power supply is taken from the back end of the MT will only switch off, or when the power supply into the bright.

5, if there is an external power supply, there will be displayed.