May 26, 2014

High Voltage Quality Testing on Extrusion Lines and Rewinding Processes


When companies want to improve the quality of their products, there can be little doubt that the purchase of new measuring equipment is on the agenda. To begin with, the estimated reliability and the validity of the collected data is carefully weighed against factors such as safety, standards and value for money. This is especially true if the capital investment aims to secure accurate quality control on extrusion and rewinding processes.


New Generation of Spark Testers

The high voltage testing with DC spark testers of the DST 28A series and the AST H 15A high frequency spark testers extend the application spectrum of the spark tester product range from Zumbach. They meet all requirements to ensure you never lose sight of quality standards during the extruding or rewinding process. The spark testers instantly and reliably detect defects and faults on the sheathing and insulation of electrical cables, tubes, corrugated tubing, hoses and similar products. Install these devices to make sure that defective products with bare patches, hairline cracks or pinholes have no chance of slipping into circulation. As soon as a fault is detected, the system triggers an alarm. Every fault is logged.


Continuing operations after spectacularly short loading time

Once the fault is outside the electrode, the spark tester continues operations after an unbelievably brief loading time and resets the test voltage to the default value. On rewinding devices, the faults are consecutively counted. The test voltage is disconnected on fault detection. An alarm message is sent via the interface, or the potential-free alarm contact is activated.


ASTH15A_DST28A_280        ASTH15A_DST28A_BAE_280


The high frequency models of the AST H 15A series test the dielectric strength of insulation layers and cable sheathing on wires and cables with a diameter of up to 30 mm. These spark testers feature bead chain electrodes in accordance with UL 1581.

Key technical information

Test voltage 0.5 to 15 kV AC
Product diameter up to 30 mm
Frequency 2.5 to 4 kHz


The DC models of the DST 28A series can be used in a variety of scenarios, for example to test products made of sensitive materials, tubes, hoses and for dry cable applications with an insulation thickness of up to 3 mm. These spark testers are ideal for quality testing on high-speed production lines. Depending on the product, bead chain, bronze brush or carbon brush electrodes are used.

Key technical information

Test voltage 1 to 28 kV DC
Product diameter:
up to ø 30 mm with bead chain electrodes
up to ø 75 mm with ring electrodes (bronze or carbon brushes)
60 x 30 mm with flat electrodes (bronze brushes)


The electrode units in both systems feature a solid electrode, a controlled high voltage generator, a fault detector and a selection of multiple interfaces, Profibus/Profinet, Ethernet etc. This makes it easy to integrate the spark testers in existing quality monitoring systems. A potential-free digital/analogue input or output is optionally available.

With an additional BAE 2 SP display and operating unit, the electrode unit can also be manually controlled. The device with a swivel mount is attached on the electrode unit for operation from any direction.

The benefits at a glance

• Best suited for highest capacitive loading capabilities
• Continuous and faultless detection of defects in insulation or sheathing of electric cables
• Detection of defects in the wall thickness at pipes, hoses, corrugated pipes and similar products of made of insulating materials
• Regulated, adjustable output voltage up to 28 kV DC (DST 28A)/ 15 kV AC (AST H 15A)
• Full range of electrodes • Detection of pinholes and bare patches on cables and tubes with diameters of up to 70 mm (DST 28A); up to 30 mm with AST H 15A
• Compact design
• Designed for a wide range of standards, incl. IEC 62230, UL 1581, UL 2556

The full spark tester product range from Zumbach covers test voltages of up to 40 kV for products with diameters of up to 200 mm.

Further Information

AST H 15A und DST 28A online
Fact Sheet DST 28A (PDF)
Fact Sheet ASTH 15A (PDF)

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