Video: AMIC-5005

Video transcript

a cable, a motor or a breaker goes back into service, its insulation has to be proven. A DC test at up to 5 kV, read over time, shows moisture, dirt, and aging before a breakdown. Any test voltage from 50 V to 5 kV. Resistance up to 50 V to 5 kV. A test current of 1.2 or 3 mA. And, with every result, the capacitance and the leakage current of the object.

The range grows with the test voltage. 500 G at 250 V, 2 TΩ at 1 kV, 15 TΩ at 5. The voltage itself follows the rating of the object. the right, the three test sockets, plus, the guard G, and minus, with a shielded socket. Below them, the rotary switch picks the test voltage, step voltage, or dielectric discharge. The F keys set the parameters.

START runs the test. In the bag, three test leads, 1.8 m long and rated 11 kV, in red, blue, and shielded black, with crocodile clips and pin probes. Also, the mains cable, the USB cable, and the calibration certificate. Leads up to 20 m or options. Every test follows the same order. Switch the object off and earth it. Connect the leads, then remove the earth.

Choose the voltage and set the times with menu. Hold start, or lock it with enter. At the end, the meter discharges the object by itself. On a multi-core cable, each conductor is tested against all the others. Bond L1, L2, L3, and end together, and earth them. The red lead, RISO+, goes to that bonded group. The black lead, RISO-, goes to the conductor under test, here PE. Then move on to the next one.

A long cable is a large capacitor. Keep its cores earthed until the leads are on, and never pull a lead during the test. After the automatic discharge, earth the cores again. The voltage can build up once more. a high-voltage circuit breaker, a damp insulator surface can carry more current than the insulation itself. The red lead goes to the earthed frame.

The blue guard lead goes to the insulators of the terminals. The black, shielded lead goes to the terminal. Surface current now flows to G and stays out of the result. As the insulation polarizes, the reading rises. Two ratios sum up that curve. DAR is the 1-minute reading over the 30-second reading. PI, the 10-minute reading over the 1-minute reading. A beep every 5 seconds helps to follow the curve by hand.

In the SV mode, the meter applies five voltages in a row, up to the voltage you set, for example, one to five kilovolts, each for 30 seconds to five minutes. Sound insulation gives the same resistance at every step. A resistance that falls as the voltage rises points to a weak spot. The dielectric discharge test charges the object, then measures the current one minute after the test voltage is removed. Divided by the voltage and the capacitance, it gives DD, a figure that does not depend on the test voltage.

Below two is good, above seven bad. In a live substation, below 50 volts DC or 500 volts AC of interference, the test goes on and noise is shown. Above that, it is blocked. Digital filters of 10, 30 or 60 seconds steady the reading. Results go to 990 memory cells and transfer over USB or Bluetooth to the PC software. A mobile app shows the graphs live and can control the test from a distance.

Measuring Category 4 at 600 volts. A case rated IP67 when closed. At least 1,000 tests on one battery charge or power from the mains. And about six kilos. Distribution and power transformers, motors and generators, single core and multi-core cables, capacitors and switchgear. In substations, power plants and industry, at commissioning and in periodic maintenance.

Insulation resistance testing from Amperis.