7 important factors and operating procedures to consider when calibrating a clamp meter
The current clamp meter measures current in a non-contact manner, making it more convenient to obtain measured values. Current clamps often have additional measurement capabilities such as voltage and continuity. Clamp meters generally require annual calibration to ensure they can maintain the manufacturer's specifications.
Here are 7 important factors to consider when calibrating a clamp meter:
1. Clamp meters come in a wide variety of shapes and sizes.
The jaw size design makes the calibration process somewhat difficult, and corresponding calibration equipment needs to be selected.
2. Most clamp meters today are multi-functional.
In addition to current, most clamp meters can generally measure voltage, continuity, and other functions common to digital,
3. Not all calibrators are up to the job.
At higher outputs, many calibrators limit the continuous output of large currents. Additionally, you must use a calibrator that is accurate enough and has a compliance voltage sufficient to drive the coil. Fluke uses "L-COMP" (inductive compensation) technology to increase compliance voltage to drive the load.
Coil inductance can cause malfunction, so avoid current sources not designed for current coils. Transients when turning current on and off can cause the current source to trip.
4. The winding (number of turns) and measuring range of the current coil are very important.
The number of turns of the coil used must be sufficient to test the entire current range of the current clamp. The coil winding determines the amount of current. For example, a 50-turn calibrator outputting 20 A will appear as a higher current of 1,000 A on the clamp meter.
5. Don't ignore attachments.
Some clamp meters may be equipped with flexible current probes, such as the Fluke iFlex, which must be calibrated along with the clamp meter.
6. High current will generate heat.
The current coil must be designed to dissipate as much heat as possible. Coils typically have maximum operating time specifications at higher currents.
7. Positioning is very important.
When aligning the clamp meter with the current coil, be aware of current clamp stray fields and position sensitivity. Avoid interference fields from other devices and current lines. Note the clamp meter alignment marks. Align the axis of the clamp meter parallel to the axis of the coil, and align the flat surface of the jaw perpendicular to the coil wire.
