We manufacture a small system with two threephase motors 230 V.
The system is connected to single phase 110 V. In the control the following components are used:
A PLC Siemens Simatic S7-200
2x VFD Siemens 6SE6420-2AD24-OBAO
A transformer 110V-230V.
By this design we get a leakage to ground approx totally 20 mA at 230 V. We have sold this unit in Europe and Asia with no problems. Either an earth leakage circuit breaker (ELCB) of "industrial type" = at least 30 mA (230 V), sometimes higher (100 mA), is used or the equipment is used without any ELCB.
We have runned into problems in US. Our customers claims they have to use a GFI that trips by 5 mA. By definition we know that this is impossible to reach with the design including the two VFD's. How to act?
Can units be operated without a GFI?
Are there industrial types of equipment that allows higher leakage than 5 mA?
The system is connected to single phase 110 V. In the control the following components are used:
A PLC Siemens Simatic S7-200
2x VFD Siemens 6SE6420-2AD24-OBAO
A transformer 110V-230V.
By this design we get a leakage to ground approx totally 20 mA at 230 V. We have sold this unit in Europe and Asia with no problems. Either an earth leakage circuit breaker (ELCB) of "industrial type" = at least 30 mA (230 V), sometimes higher (100 mA), is used or the equipment is used without any ELCB.
We have runned into problems in US. Our customers claims they have to use a GFI that trips by 5 mA. By definition we know that this is impossible to reach with the design including the two VFD's. How to act?
Can units be operated without a GFI?
Are there industrial types of equipment that allows higher leakage than 5 mA?