Dependence of the DC link voltage UA on the voltage UB for MDP92A..

[1]	A-side: DC link busbar, input end
[2]	B-side: Connection of energy storage unit or DC supply system

To ensure that the standard specifications regarding the creepage distances are adhered to, the permanent level of the voltages +U_Z to ground, +U_B to ground and -U_Z to ground each must not exceed 546 V.

This only leads to restrictions when connecting an isolated DC supply system, such as a DSK or a battery, on the B-side. The use of an insulation monitor is mandatory in the insulated DC supply system. The insulation monitor must be connected on the B-side in order to keep the voltage +U_B to ground and -U_Z to ground symmetrical. As a result, the voltage -U_Z to ground is half as high as the voltage U_B.

As shown in the image above, The negative potential of the A-side (-U_Z) is identical to the negative potential of the B-side (-U_Z) in MDE90A... As a result, the maximum DC link voltage U_A is the sum of the voltage -U_Z to ground plus 546 V.

The following table shows examples of this restriction for isolated DC supply systems, which must be taken into account during project planning:

The limitation of the DC link voltage U_A does not apply to regenerative energy. In the event of an error or incorrect project planning, the device automatically limits the maximum DC link voltage U_A depending on the detected voltages to ground.