IEC 60990 Figure 5 Touch Current Measuring Circuit Test Equipment

Product information:

This test network conforms to the measuring network requirements of IEC 60990 figure 5 touch current and the measurement method of protective conductor current,

(Figure 5- Measuring network, touch current weighted for letgo-immobilization), it is required by IEC 62368-1:2018 clause 5.2.2.2, etc.

An electrical energy source class is determined from both the voltage and the current under normal operating conditions, abnormal operating conditions, and single fault conditions.

Preparation:

Before testing, you need to prepare instruments as follow:

Oscilloscope x1

One or ten times the voltage probe x1

Power supply x1 (the test voltage or frequency that can be adjusted or changed to the required voltage or frequency)

Test Method

• Adjust the power supply to output the required test voltage and frequency, and then plug the input terminal of the touch current test conversion switch into the power supply. (please do not electrify when the network is not connected.)
• Insert the sample into the output terminal of the touch current test conversion switch.
• Connect the port B of touch current test conversion switch with the port B of touch current measuring circuit.
• Connect the port A of the touch current measuring circuit to the place where the touch current is required. Such as connect the port A to the adapter’s output or shell when the network adapter is tested.
• The Oscilloscope probe is clamped into U1 or U2 terminals according to the test requirements.
• Connect the power supply, put switch “N” to the on position, put the positive phase to the positive phase position, switch line “G” to on position, check whether the tested sample is on work by normal electricity and is there a waveform on the oscilloscope.
• According to the standard requirements after the sample is working, in the different mode of “positive phase”, “reverse”, “N line on”, “N line off”, “G line off”,“line G on”and so on, read voltage U1 and U2 directly by using oscilloscope, the touch current is equal to the peak value of U2 and then divide 500.

Notice

1. During the test, it is necessary to pay attention to safety because you can touch some terminals.

2. According to IEC 60990 standard requirements, the power supply must be in isolation, and zero line and ground wire must be connected together. (the simple way is to whether there exists voltage on zero line and ground wire, if voltage surpass 2V, such as 220V power, the different voltage between zero line and ground wire more than 100V, the zero line and ground wire must be connected.)

3. When testing, please pay attention to the polarity of the power supply. The fire line must be connected to the L end of the contact current test conversion switch. If the connection is wrong, there is a danger of electric shock.

4. Connect the oscilloscope, test the sample, then connect the power after b-terminal line, and do not connect the test line when the power is connected.