Insulation parameters meters

Insulation meters are used by electricians and high-voltage installation technicians. Measuring the resistance of circuits, insulating materials, electric motors, and telecommunication networks makes it possible to establish the safety level of the object being tested.

What tasks do meters solve?

Using measuring instruments, the dielectric loss tangent of high-voltage insulation of transformers, bushings, capacitors, and liquid dielectrics is determined. Dielectric loss is the energy that is dissipated in insulating materials when exposed to an electric field. In addition to this value, such devices allow you to measure phase shift, frequency, voltage and current vectors.

An increased dielectric loss tangent indicates aging of the insulating material, the presence of moisture and partial discharges in it. Measuring the dielectric resistance makes it possible to find local damage and assess the moisture level of the transformer windings.

Types of instruments for measuring resistance

To determine resistance use:

• Ohmmeters are specialized devices used only to determine resistance. Typically, measurement is carried out using direct current, and only in some models — using alternating current.
• Megaohmmeter. Designed to determine large resistance values. During measurements, a high voltage current is supplied to the circuit.
• Multimeter. To measure resistance, turn on the required mode. Multimeters are digital and analog. The first type of device has a monitor on which the measurement result is displayed using light indicators. The analogue one has a glass window with a scale and arrow. The digital multimeter has a light indicator that indicates the presence/absence of charge in the battery. An analog device produces erroneous readings when the battery is discharged.

Recommendations for choosing a suitable resistance meter

When purchasing a measuring device, consider:

• optimal measurement range;
• voltage values at which measurements can be carried out;
• operating temperature range — models can be designed for operation only at positive temperatures, but there are devices for winter use.

Questions and answers

What is the frequency of insulation resistance measurements?

The frequency of measurement activities is determined by regulatory documentation. Standard options:

• mobile electrical installations — once every six months;
• outdoor electrical installations, wiring in electrically hazardous rooms, cables in lighting lines — once a year;
• electrical appliances, low-power electrical equipment — once every 3 years.

Can a multimeter be used for professional purposes to measure resistance?

In professional work, megohmmeters are used, which best cope with the measuring task.

What are the insulation resistance standards for different electrical installations and electrical circuits?

Some standard indicators:

• cable wiring in regions and facilities with normal climatic conditions — 0.5 MOhm;
• stationary electric stoves — 1 MOhm;
• electrical devices consuming voltage up to 50 V — 0.3 MOhm;
• electric motors and units that require a voltage of 100–380 V, 0.5 MOhm and higher.

Advantages of cooperation with STEMAG GROUP

At the STEMAG GROUP company you can select from the catalog and buy an insulation parameter meter, price — on request. We work only with legal entities. You can pick up your order yourself or order its delivery to your destination using transport companies or courier services.

The company provides:

• supply of high-quality instrumentation from reliable manufacturers;
• professional advice on all issues of interest to the buyer;
• prompt order fulfillment.