Surge generators are used for producing the high-voltage pulses, by charging the capacitors in parallel and discharging them in the series combination. This article will let you understand how we can conduct a DC HiPot and the surge tests.
Surge tests are considered critical because they are known best for finding turn-to-turn insulation weaknesses. These weaknesses begin at voltages above the operating voltage of the motor. They are the main causes of serious failures and the shutdown of a motor. Surge tests are also used for finding the hard shorts and several other mistakes in windings and coils.
They are also known as the “surge comparison test” because the result obtained from one coil or phase is compared with another coil or phase. The reason for this act is that the coils are almost identical, so the results obtained are also identical to some extent. If the coils are not identical, the test is called the “pulse-to-pulse test”.
Detection of some failures with surge test
The surge test can detect some known failures in the underground cables. Some of them are listed below;
• Turn-to-turn weaknesses and shorts
• Coil-to-coil weaknesses and shorts
• Phase-to-phase weaknesses and shorts
• Wrong turn current
• Wrong coil or group connections
• Short to ground
• High partial discharge
• Weaknesses to ground
• Partial blowout of random wound coils
What is a”surge master generator”?
A surge Generator is considered the backbone of an underground cable fault locator test system. It is used with a Prelocator for the measurement of fault distance. It is also used with a PinPointer to find the fault spot’s location.
LISUN stocks the surge generators for multiple tests like immunity and surge tests and conducts compliance immunity tests. These surge generators mostly include a network of coupling and decoupling. This network can apply the power to the device under test for up to 16 AMPs.
DC HiPot and Surge Testing
• Connect the braided ground cable to a known earth ground point. Connect the test leads to the motor’s stator and ground lead to a paint-free point on the frame of the motor.
• Connect it now if you have the optional footswitch accessory—power on the power pack and the DX.
• Verify that the voltage control knob is zero as a safety feature.
• The test leads are connected to the high voltage power supply, the warning lamps on the power pack will light up, and the words lead energised will appear on the DX’s screen.
• If, for any reason, you need to disconnect the power to the test leads quickly, press the equipment stop button.
• This can be reset by turning it. Let’s start with the DC high pot testing.
• On the main screen of the DX, select the DC test. Select the power pack configuration.
• Select either thermoplastic or thermosetting corresponding to the type of insulation being tested. Enter the stator winding temperature.
• Turn the test selector switch to the high pot. It is important to note that only the lead 1 will be energised during the high pot test.
• Turn the power pack function switch to the 100 microamps per division position.
• If you have one, press and hold the push to test button or press and hold the footswitch.
• Smoothly, turn the voltage control knob to raise the voltage to your first step.
• In this case, it is 10,000 volts. Press the step button to initiate the step timer, which will be one minute long by default. On the other hand, the voltage is held at a constant value.
• The leakage current will diminish over time if the current value falls below half of the lowest division.
• Turn the power pack function knob to 10 microamps per division. The leakage current will continue to diminish if it again falls below half of the lowest division. Turn the Power Packs Function to 1 microamp or division.
• Watch the seconds remaining countdown.
• Return the Power Packs Function knob to 100 microamps per division when the step timer is complete. This will avoid an overcurrent trip.
• When you increase the voltage, turn the voltage control knob smoothly to increase the voltage to the next desired level.
• Adjust the current scale with the function knob as before. Continue this procedure for all steps.
• However, press the DC high pot instead of stepping again when you reach the final test voltage.
• This test will last for one minute by default.
• When the high pot test is completed, release the push to test button or the footswitch.
• Save all the data.
• Return the voltage knob to zero. Turn the test. Select the knob to the lead ground position that the X will remind you to do this.
• To ensure the test circuit is adequately discharged, maintain the ground connection after testing for the same duration as the high voltage was applied.
• Now, we will perform surge testing on a three-phase motor on the main screen of the DX. Select the surge test.
• Select the power pack and verify that the voltage control knob is zero. Press the Power Pack function switch to the surge test position.
• Turn the test, select the knob to lead 1 and check that lead 1 is highlighted yellow on the DX.
• Press and hold the push to the test button or footswitch.
• Slowly increase the voltage knob until the surge wave can be seen, and then adjust the horizontal scale so that the waveform is shown across most or all of the screen.
• Slowly and continuously raise the voltage to the desired test value. In this case, 14,000 volts.
• Turning the knob smoothly minimises the effects of ramping on the pulse to pull the CER.
• Release the push to test button or footswitch. Select the lead on the power pack and press to on the DX.
• Turn the voltage control knob to zero. Press and hold the push to the test button or the footswitch.
• Slowly increase the voltage to the desired test value as before.
• Repeat the procedure for the lead 3.
• Save the data.
• Turn the voltage control knob to zero and the Power Packs test. Select the switch to the lead ground.
Frequently Asked Questions
Q: Is it a normal case for any generator to create surges?
A: This phenomenon in which a generator surge is referred to as surging. Power surging caused by the generator is never considered a normal case. It is a sign that something somewhere within your generator is not performing its function effectively.
Q: Do the surge protectors work with the generators?
A: Yes, you can use a surge protector with your generator. Suppose you think that a surge caused by your generator can destroy your house’s appliances and electronic devices. In that case, the only solution to resolve this problem is to attach a surge protector.
Lisun Instruments Limited was found by LISUN GROUP in 2003. LISUN quality system has been strictly certified by ISO9001:2015. As a CIE Membership, LISUN products are designed based on CIE, IEC and other international or national standards. All products passed CE certificate and authenticated by the third party lab.
Our main products are Goniophotometer, Integrating Sphere, Spectroradiometer, Surge Generator, ESD Simulator Guns, EMI Receiver, EMC Test Equipment, Electrical Safety Tester, Environmental Chamber, Temperature Chamber, Climate Chamber, Thermal Chamber, Salt Spray Test, Dust Test Chamber, Waterproof Test, RoHS Test (EDXRF), Glow Wire Test and Needle Flame Test.RWG61000-12 , SG61000-5