25kV DC, 50mA Continous, Mains Powered Proof Tester
Test engineers and technicians need to proof test cables and switchgear after installation or rework to existing systems. The Adret range of proof testers was designed with simplicity of use and maximum operator safety in mind. The range offers many different models from DC to AC and VLF (very low frequency) as well as combination AC and DC models.
PRINCIPLES OF OPERATION
All the units use the input voltage through a step up transformer to obtain the high AC voltages. In case of DC output the AC is rectified through a suitable rectifier capable of withstanding the high voltages. Some units use a combination of AC and DC that is switched to deliver AC or DC or both. In the case of VLF equipment a pseudo sine wave is produced through a number of switches and resistors.
The outputs are current limited and the unit automatically trips when a set limit is reached. When this occurs the cable is discharged and made safe through a built in discharge resistor. In case the circuit layout does not allow (in case of split units) the automatic discharge of the cable, a suitable manual discharge resistor is supplied The units are portable and simple to operate.