Your local contact:Know How
RC link in the insulation test
Why is that?
There is insulation between the two test connections of a test specimen. This insulation acts like a very large resistor, through which normally hardly any current flows. It is precisely this resistance that you want to evaluate during the test, because it says something about the quality of the insulation.
In addition, the device under test but also like a small electricity storage system. This is because there are metal parts inside that are separated from each other by insulating material. Such arrangements save electrical charge – similar to a capacitor.
The larger these metal surfaces are or the closer they are to each other, the stronger this effect is. This "storage effect" is therefore particularly pronounced in large motors or stators.
What happens during a high-voltage AC test?
If the test is carried out with alternating voltage (AC), this electricity storage unit is constantly recharged and reactivated. discharge. Compared to the current, the insulation resistance, a comparatively large stream that is generated solely by this reloading.
This stream:
- is physically normal,
- always occurs,
- says nothing about the quality of the insulation.
The actual Test currentthat would flow through poor or damaged insulation, on the other hand, is very small. It is practically overlaid and concealed by the constantly flowing flow of reloading.
What does this mean for the assessment?
The current measured in AC tests consists largely of this mostly harmless transfer current.
Therefore, it is only suitable to a limited extent for evaluating the quality of the insulation. Although the current must not be too high overall, it is not possible to make a reliable statement about the insulation condition from its height alone.
Advantage of the high voltage test with DC
In the case of a high voltage test with direct current (DC), the TEST VOLTAGE slowly and evenly. During this phase, a charging current initially flows, as the device under test behaves like a small electricity storage device. At the same time, a very small current is already flowing through the insulation.
With increasing voltage the current increases proportionally due to the insulation. As soon as the TEST VOLTAGE has reached its final value and does not increase further, the charging process is completed. The previously existing charging current disappears, leaving only the current that actually flows through the insulation.
Only after this charging phase has been completed is it possible to make a meaningful measurement of the insulation resistance.
Why is DC at an advantage here?
In contrast to the AC test, the DC test does not generate a permanent transfer current.
The Capacitance current only flows during the voltage ramp. As soon as the voltage constant, only the insulation current remains.
This means:
- The current measured after the voltage ramp directly depends on the condition of the insulation
- Disturbing capacitive currents hardly affect the measurement result
- The assessment of insulation quality is much more reliable
Test devices and Test systems
HandHeld
Protective earth conductor and insulation resistance test device
- protective earth resistance test up to 10 A AC
- Insulation resistance test up to 1,000 V
- Mobile use – lightweight – for indoor and outdoor applications
- Carrying strap
- Transport case
- PC software included
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Technical Service for Hospitals
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Rotor blade lightning protection test for wind turbines ...
GLP1-g insulation resistance test devices
- DC 50 – 1000 V | 5 mA
Ideal for
- Manual Tests with Test Tips
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- OEMs, system integrators
- Communication with PC, PLC, LabVIEW®
GLP2-BASIC
Protective earth conductor, insulation, high voltage, leakage current, resistance, and functional test device
- Insulation test devices
- High voltage test devices AC/DC
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- Network
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- Desktop device or 19″ rack mounting
GLP2-MODULAR
Multifunction test device with up to 25 test methods
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- PL e, SIL 3, two-hand control Type III C, Cat. 4 safety circuit (depending on device variant and degree of hazard)
- Network
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GLP3
Class-leading test technology unlimited
The top class of test and measurement technology for safety & function test.
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MotorAnalyzer3
The mobile ALL-IN-ONE professional model for your Motor service
CHECK YOUR MOTOR'S HEALTH!
For electric motor service and repair
For electric motor repair
For maintenance, servicing, and service
- Globally unique – the mobile ALL-IN-ONE test device
- AutoTest – the fastest troubleshooting
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- surge test up to 3 kV | 0.45 Joule
- High voltage DC up to 6 kV
- Insulation up to 500 GΩ
- Polarization index and DAR
- LCR measurement
- Automatic measurement between the four relevant Connection points of the three-phase Motor
- three winding Connections
- one housing Connection (laminated core or Motor housing)
- Communication with
«» PC via Bluetooth
MotorAnalyzer1
The entry-level model for your Motor service
CHECK YOUR MOTOR'S HEALTH!
For electric motor service and repair
For electric motor repair
For maintenance, servicing, and service
- Universal stator-, armature-, Motor- and transformer testing equipment
- 10 built-in test methods
- Automatic measurement between the three Connections of a three-phase Motor
- Built-in results database
- Transmission of the results via RS-232 or USB interface to the PC
- Mains-independent battery operation with battery status indicator
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- Ideal tool for on-site use and for the workshop
MTC2 R7
Universal winding Test devices 6, 12, 15, 30, 40 and 50 kV
MTC2 winding Test systems are very compact, fully automatic high-end Test devices for a wide variety of winding goods in development, production, and Test laboratory.
For production, EOL, automation
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surge test
-
- Ultra-fast 50 measurements per second
- Phase comparison between phases
- Patented peak-to-peak measurement
Partial discharge compliant with DIN EN 60034-18:2014
-
- Passive or active antenna
- Conducted coupling
ohmic resistance
-
- Winding
- Temperature sensor
insulation resistance
-
- IR
- PI
- DAR
High voltage AC optional
Test connections
-
- Standard: 4
- Optional: 7 and more
MTC3 R2
The high-end test systems for Motor production – without limit
MTC3 winding test systems are fully automatic high-end test devices for various winding goods in development, production, and test laboratories.
For production, EOL, automation
For test laboratory, R&D, approval, certification tests
- Testing of stators, rotors, transformers and inductors
- Surge test up to 15 kV
- Fully built-in partial discharge test according to IEC 61934 and DIN EN 60034-18-41
- Resistance measurement in four-wire technology with temperature compensation
- Insulation resistance test with automatic PI measurement
- Inductance test | LCR inductance measurement bridge
- High voltage test AC according to VDE standard
- Partial discharge at high voltage AC
- Insulation test DC
- Precise four-wire resistance measurement with temperature compensation down to the µΩ-space
- Rotating field test with static probe
- Expansion to up to 150 connections
- Temperature sensor test for 1, 2, 3 … x sensors
* indicates required fields