This rack cabinet, complete with electrical safety features, is born out of the necessity to utilize direct current power supplies with currents up to 30 amperes and a maximum voltage of 600V, ensuring maximum safety for operators who need to use it for testing or other applications in compliance with workplace safety regulations D.lgs 81/2008 and work procedures compliant with CEI 11-27.
The safety system described here allows the installation of any rack-mountable power supply with a continuous current output, provided it is galvanically isolated between AC input and DC output.
In the case of using power supplies whose output voltage exceeds 50V AC and/or 120V DC, it is essential to use all possible protections to safeguard operators.
In this specific case of rack cabinet usage, a system composed of a bidirectional power supply Elektro-automatik EA-PSB9500 3U is proposed, within which a series of safety measures have been implemented for operator protection.
Listed below are the main safety measures implemented in the system:
- Front and rear door lock with key.
- Interlocked network power switch at 380V input, lockable.
- Remote control panel.
- Protection and power lockout on output in case of high voltage direct current output connector disengagement.
- Visual indication via optical display of residual voltage at DC output contactor in open condition, less than or greater than 50V DC on user side.
- Protection and power lockout on output in case of lack of insulation towards ground.
The system intervenes by blocking the output current delivery in case of insulation lacking below an adjustable threshold from a few kOhms up to 500 kOhms towards ground with continuous measurements through a specific module contained within the cabinet.
This insulation meter used for detecting insulation faults operates on IT type distribution systems (isolated from ground) on the DC side of the power supply.
The insulation meter is connected to the DC output conductors and ground and can work on a powered system up to 600V DC.
Emergency mushroom switches on the front panel and on the remote control console.
Inside the cabinet, protections have been implemented with circuit breakers, differential circuit breakers, fuses, and operator safety relays.
An example of usage for the system could be to power a full electric or hybrid vehicle system for various testing purposes.
FOR FURTHER INFORMATION, PLEASE REFER TO THE PDF AT THE BOTTOM OF THE PAGE
