How to use clamp meter.Hello today I’d like to show you how to use a current clamp meter we will use. The popular unity UT 202 a and the unity UT 203 models to demonstrate first.
You can watch this video for detail information.
Let’s talk about what a clamp meter ? Actually is the clamp meter is a meter device capable of measuring current without direct contact to that current. This is one of the main advantages of a clamp meter compared to traditional ammeters and multi meters.
You don’t need to break the circuit to conduct measurements. You can actually conduct measurements of the line under voltage as well as measuring high currents operational safety is one more advantage. You are able to measure the current of an insulated conductor.how to use clamp meter.
Measuring current with these meters is really simple. You just switch to the required measuring range of current. In our case it’s 600 amps press the trigger to open up the clamps jaws and place the conductor you want to test inside and close the clamp the display.
Then shows the measurement results the main element of a clamp meter is the current sensor. There are two types of sensors used one type is a current transformer and the other is a hall sensor. Depending on the sensor used the meter may measure either alternating current or direct.
An alternating current here we have a clamp meter with a current transformer in this meter inside the plastic housing here. There is a magnetic core if you open up the clamp. You can see part of it. The conductor that measures the current acts as the primary winding and the secondary winding is inside the plastic housing.
We aren’t able to see that the main
advantage of this type of design is
having a low price and simplicity. The drawback is that it’s a transformer. So you can only measure alternating currents. The other type of design of clamp meters instead has a Hall sensor there is no magnetic. And if you open up the clamps jaws you can see that the advantage is that the hall sensor can detect both alternating and direct currents.
However the disadvantage is it’s higher price. So let’s start with some alternating current measurements. The main thing you need to remember for measuring current is that you have to clamp exactly the conductor that you want to measure like this. So if we clamp both sides at a time or the whole cable we will get a zero result. Because the meter only detects the difference between the currents.
Because both of these conductors carry the same current the difference will be zero. So if you have a cable consisting of several wires and you need to measure each of them. You don’t need to strip anything like we have here you just need to find a place where the cable is divided into separate wires. For example somewhere in the electric cabinet and then start measuring.how to use clamp meter.
The second most important thing to remember when measuring current is setting the correct measurement range. If you are not sure about what current range to use you have to start with the maximum. Let’s demonstrate this right now I’m going to measure the current used to power this electric teakettle. Let’s assume that I don’t know what current is being used. But it has to be lower than 600 amps.
I turn the kettle on and switch the meter to alternating current with a 600 amps range. Now we’ll put the clamp on the wire. The kettle uses some current about 7 amps. Let’s switch to a lower range 200 amps we get 7.6 amps. To measure the current with the best accuracy possible I’ll switch to the 20 amp range the meter shows 7.73 amps. If I clamp both wires I’ll get something around 0.
You have to follow the rule of only clamping one conductor. Now let’s take the meter with a Hall sensor the measurement procedure is very similar. One difference though is that you have to set the readings to zero before starting a new measurement.
Because the hall sensor is magnetically sensitive. So first i zero the display readings and then measure we get a current of slightly less than 8 amps. Now I will use the UT 203 clamp meter to measure current under real time conditions in a 3 phase circuit.
First we turn the rotary switch to the current measuring position and then switch to alternating current measurements. Let’s start with phase a 47 amps we can press the hold button to store the result. Now the second conductor 27, 8 and the third conductor 46 amps.
And now will demonstrate some direct current measurements we have a power supply unit providing three amps of current in this circuit. First we’ll switch the meter to the 40 amp range. Because the hall sensor is very sensitive. we need to zero the display readings and now we can measure the conductor.
It shows three point one five amps. the Absolute accuracy is about 150 to 170 milliamp but that is not much taking into account that our measuring range is 40 amps. A current transformer clamp meter cannot measure this current. At all these two models like most modern clamp readers in addition to current are capable of measuring voltage and resistance. And they have a continuty buzzer and diode test functions.
They are fully functional multimeters with a non-contact current measurement function.how to use clamp meter.