The TOS9300 series of electrical safety testers is a robust all-in-one solution. When performing AC Hipot, DC Hipot and Insulation Resistance tests there are setting options which allow the user to optimise testing as necessary for all applications. In certain situations where EUT’s are being tested for very high insulation resistances the LPF can be used to significantly improve the accuracy of the tester.

WHEN TO USE THE LPF SETTING
The LPF of the TOS9300 series is a second order Bessel filter with a 3dB cutoff at 1 kHz. This filter was designed to remove the transmission line noise that causes stray capacitance to affect the measurement. Any application that expects an insulation resistance measurement higher than 50 M ohm should consider using the LPF.
When measuring high insulation resistances at high voltages we expect to see very low currents measured at the ammeter because of Ohm’s Law. Readings where the expected current is only nA are greatly affected by high frequency noise. This type of noise is hard to avoid so it is useful to have a LPF which removes the high frequency current components just before measurement. It should be noted that a longer test time should be used to compensate for the lower frequency signal being measured in the test. See the operation manual for more information.

Products Mentioned In This Article:

• TOS9300 Series please see HERE

In this white paper, we are going to share the techniques to make the system that our bipolar power supply PBZ Series acts as a constant resistance load.
1. System Details
First, we are describing the system. See Figure 1 below; two units of PBZ20-20 are required for the system to operate as an AC electronic load ‘PBZ20-20’ and an AC power supply ‘PS (PBZ20-20)’:
1. CC mode is set on PBZ20-20.
2. The resistances are placed at the output terminal of PBZ20-20 to divide the voltage.
3. The divided voltage is applied via EXT SIG IN (BNC) to control the output current from PBZ20-20.
4. When the AC voltage is applied from PS, PBZ20-20 operates as a constant resistance load.
5. To adjust the current, connect a variable resistance (VR1) to EXT SIG IN.

2. Test Results
Next, let’s look at the test results on this system.
Given below are the phase relationships between the voltage and current under this system. Figure 2 – 6 show the input AC voltage waveforms and current waveforms:
Test Conditions: PS PBZ20-20: 40 VP-P, PBZ20-20: 40 AP-P specified by VR1 Waveform in blue: Voltage, Waveform in light blue: Current

3. Conclusion
As the frequency is getting higher, the current leads the voltage. This implies that PBZ20-20 operates like a capacitive load at the higher frequency in this system. When the sinewave frequency is 8 kHz (Fig. 6), the phase difference between the voltage and the current is approx. 28°. From this phase difference, the power factor will be 0.88.

Products Mentioned In This Article:

• PBZ Series please see HERE

For PBZ Series, a magnetic relay is used to turn the output on/off. The relay is off to turn the output off; when the output is off, the output is in the high impedance state.
In addition, if the output-on/off is controlled by an external signal input, the embedded firmware in PBZ may cause a jitter on the output voltage.
Now we are going to focus on the following two topics of the output on/off behaviour of PBZ and explain how:
1. the output voltage and output impedance change during the output on/off operation
2. PBZ responses to the output-on/off external signal input.

1. Change in Output Voltage and Output Impedance during Output-On/Off Operation
Figure 1 shows: change in the output voltage (Vout) and output impedance when the output is turned on. Figure 2 shows: change in Vout and output impedance when the output is turned off.
* The rise and fall time of Vout is dependent on the response setting by PBZ.

1-1. Output On

1-2. Output Off

Output Impedance:
High:
・ PBZ20-20: 120 kΩ ・ PBZ40-10: 220 kΩ ・ PBZ60-6.7: 320 kΩ ・ PBZ80-5: 420 kΩ Low:
・ a few hundred Ω Very Low:
・ Output is turned on.

1-3. Recommended Method to Frequently Turn Output On/Off
If you want to repeatedly switch the output on/off over a long period of time, we recommend the following procedures to prolong the lifetime of the relay:
1. Keep the output on.
2. To turn the output off, set the output voltage (Vset) to 0 V.
For DC output only: If you want to set the high impedance when the output is off, place a diode in series with the output terminal of PBZ and set Vset to 0 V.
* For the battery charging application, also place a diode in series with the output terminal of PBZ.
2. Output-On/Off Response to External Signal
In Figure 3 and 4, you can find the jitters when the output is turned on/off via the external signal input: ● Signal lag for output-on: approx. 90 ms max.
● Signal lag for output-off: approx. 50 ms max. ● Jitter during output-on/off: approx. 45 ms
In Figure 4, the lag between the output-off signal input and when the output impedance becomes high is approx. 90 ms max. and the jitter is approx. 45 ms; this lag is 50 ms min. and 90 ms max.
2-1. Output On

2-2. Output Off

Products Mentioned In This Article:

PBZ Series please see HERE

PCR-LE/LE2

Series can produce a DC output that enables you to test DC-powered devices such as DC-input converters. This article introduces the important precautions and useful functions to effectively operate PCR-LE/LE2 Series in DC mode.
1. Circuit Model
See Figure 1 for the test circuit model with PCR-LE. It illustrates the DC-input converter/inverter that has a capacitor-input circuit but without an inrush current prevention circuit.

2. Rated DC Current and Maximum Instantaneous Current

2-1 Rated DC Current for PCR6000LE
From Table 1;
DC input 200V: The rated DC current (maximum current) is 21A. The maximum instantaneous current, 3.6 times the rated DC current, is 75.6A.
DC input 100V: the rated DC current is 42A. The maximum instantaneous current is 151.2A. The rated DC current is 70% of the rated AC current.

From Figure 2;
Example 1) If DC input is 100V and the output voltage is DC50V; the output voltage ratio is 50% → The output current ratio is 100% → The output current equals the rated DC current.
Example 2) If DC input is 200V and the output voltage is DC400V; the output voltage ratio is 200% → The output current is limited by 50% → The rated DC current is 10.5A and the maximum instantaneous current is 37.8A.

2-2 Maximum Instantaneous DC Current
As stated above, the maximum instantaneous current is 3.6 times the rated DC current. The overcurrent protection (OCP) in PCR-LE activates when the output DC current exceeds the maximum instantaneous current. See Figure 3 for the DC current limit characteristics. DC current can remain within this limit. If the RMS DC current exceeds the limit for 1 second or more, the overload alarm is triggered to shut off the current.

3. Inrush Current
The rise time of PCR-LE is less than approx. 80μs in any response setting. While large inrush current would flow to the model circuit shown in Figure 1, PCR-LE equipped the current limit circuit can hold the DC current level to the maximum instantaneous current. If the RMS DC current exceeds the limit for 1 second or more, the overload alarm is triggered to shut off the current. The alarm can be cancelled by pressing the ALARM CLR key.
To prevent such inrush current, the power supply capacity should be increased. In PCR-LE, you just turn Soft Start on to raise the output voltage gradually and limit the current through the capacitor. To set Soft Start, press OTHERS (SHIFT + MEMORY) > RISETIME (F1).

4. Impedance when output is off
When an output is turned off, PCR-LE has a high impedance as shown in Table 2 (approx. several kΩ to several tens kΩ). As shown in Figure 4, the voltage reaches 0V for approx. 200μs when the output is turned off, and then PCR-LE is in a high impedance state. During this 200μs, the capacitor in Figure 1 discharges its electric charge and the OCP activates to shut off the current.
Table 2: Impedance when output is off

If you have any trouble during this 200μs, it is recommended that you insert a diode in series for the PCR-LE output or set COFIG > Surge Suppression > OFF to leave the high impedance (Voltage does not reach 0V). To set surge suppression, press CONFIG (SHIFT + OPR MODE) > 1/2 (F6) > SURGE S (F2) > OFF (F/W Ver.4.50 or later).
5. Others
PCR-LE uses a high-speed amplifier. The output may become unstable due to capacitive loads or wiring conditions. With such loads, we recommend that you change the response setting to SLOW to keep stable operations.
To set the response, press OTHERS (SHIFT + MEMORY) > 1/3 > RESP.

Products Mentioned In This Article:

PCR-LE Series please see HERE

Parallel operation is very useful to expand an output capacity; especially master-slave parallel operation allows you to control an entire system by one master unit.
When making the master-slave connection such as signal wiring and load connection, you may find some issues with load connection. Improper connection may cause oscillation so that our user’s manual describes how to connect the load.
In this article, you will learn not only the basic connection methods also the advanced techniques to stabilize an unstable output, which can apply to almost all our DC power supplies (except for high-speed power supply PBZ Series).
1. Basic Connection Methods
1) Make the cable connection between the master/slave units and DUT as short as possible and each connection should be the same length; In Figure 1, the cable connection L1, L2 and L3 should be the same length and then connect them to the DUT as short as possible.
2) If the above cable length is too long, connect the master/slave units to a relay terminal block as short as possible. Then, tightly twist the relay terminal block cables and connect them to the DUT at an appropriate length (See L4 in Figure 1).
See Figure 1 for the example:

*1: The L4 cables should withstand the total current from the master and slave 1 & 2.

2. Advanced Connection Methods
If the output becomes unstable under the basic connection, the following methods are available. Use all or any of three methods as required.
1) Ground either the positive or negative terminal of output (See the green lines in Figure 2). If either of the DUT input is grounded, check if short circuit may occur due to the output grounding.
For the parallel operation, you also need to check that all paralleled DC power supplies have the same control common terminal. Keep in mind that the control common terminal differs by our DC power supply series as follows:

2) Add a large capacitor to the relay terminal block (See the red lines in Figure 2). If high speed power supply such as PBZ Series has been used, avoid this method.

Products Mentioned In This Article:

To view Kikusui’s DC Power Supply range please see HERE

1. Overview

In PCR-LE Series, simulated CC operation can be achieved by setting the current limit in AC mode. This method is based on its internal system as the ammeter monitors the output current and the arithmetic circuit controls the output voltage. The functions and characteristics of this method are described as below;
1) Response becomes slow with this method.
Figure 1 shows its response when the load is rapidly changed.

2) The output current is stable if the output voltage is around the rated voltage, while the output current is fluctuated if the output voltage is low.
E.g.) The output current is stable if the load is operated by 100V voltage. On the other hand, the output voltage is fluctuated if the load is operated by 10V voltage.
3) Applied power can be limited if the load voltage fluctuation is large.
E.g.) If the load voltage starts from 100V but decreases to 50V with time due to the load resistance fluctuation, the internal loss of PCR-LE becomes larger so that its protection circuit may shut off the output.
This method has some disadvantages as stated above, however it may be useful operation for an application that the load changes slowly such as a heater.

2. Operating Procedures
Please follow the steps below to perform this method:
1) Return to the factory default setting to be safe;
– Press PRESET (SHIFT+6) key. Then, ‘RESET’ is displayed and SHIFT+ENT are flashing. – Press ENT key while holding down SHIFT key.
2) Set the output voltage and frequency to be applied.
Note) If you do not want to rapidly apply the voltage due to using the load with resistance characteristics, the following step is recommended to minimize the voltage overshoot; – Set the output voltage to low.
– After step 7, gradually increase the voltage to switch from CV to CC operation.
3) Set ‘TRIP DISABLE (Circuit breaker trip is disabled.)’ (Refer to page 34 of user’s manual: ‘Action to perform when the current limit is exceeded’);
– Press I key.
– Press TRIP key (software key). – Choose DISABLE.
4) Press ESC key to go back to the home screen.
5) Set the current limit value. This value is equivalent to the simulated CC value.
6) Press ESC key to go back to the home screen.
7) Connect your load. Turn OUTPUT on to apply simulated CC.

Products Mentioned In This Article:

• PCR-LE Series please see HERE

PLZ Series Easy Way to Expand Electronic Load Capacity in CV Mode

Our electronic load PLZ Series has a well-known feature that a master/slave parallel operation expands an output capacity in the same model, controlled slave units by a master unit (except for PLZ-4WL).
In this article, we are going to further explain how to increase the capacity by parallel connection with different models such as PLZ-5W Series (CV mode) and PLZ-4W Series.
How to Build Parallel System:
1. How to Operate PLZ-4W Series
Connect PLZ-4W to PLZ-5W in parallel and set PLZ-4W to CR or CC mode.
2. How to Connect
See Figure 1 for the example:

3. System Principle
Figure 2 shows the equivalent circuit of the above system. The red dotted line describes that the DUT and PLZ1205W are connected in parallel; PLZ1205W is in CV mode so that
PLZ1004W and the DUT should be in CC or CR operation to keep a stable operation. Note: In the example below, operating PLZ1004W in CP mode may cause an unstable operation.

4. Note
In the example above, it is necessary that PLZ1205W will not become a full load while controlling PLZ1004W; it depends on the DUT’s characteristics how to sink the current by PLZ1004W.

Products Mentioned In This Article:

Kikusui Electronic Loads please see HERE

Using Electronic Load to Battery Charger Testing

A battery charger is a device that can recharge a secondary cell or rechargeable battery. Every battery charger being used requires the testing and such testing system must include something to simulate a battery.
An electronic load can provide the best solution for the battery charger testing to simulate the actual behaviour of a battery. It is very useful to test the charger operation over the entire battery voltage range.
Test Method
Figure 1 shows the schematic diagram of the testing setup to sink the current from the battery charger to the electronic load;
● Connect an electronic load and a DC power supply in parallel.
● Operate the electronic load in constant voltage (CV) mode to keep the CV at the electronic load terminals.
● Operate the DC power supply in constant current (CC) mode to flow the CC*1 into the
electronic load.
*1: The CC is set to 100 mA.
Figure 2 shows the equivalent circuit of this testing system.
Some battery chargers determine the state of the battery first, but there is no problem in this testing system that the charger can detect the voltage at the electronic load terminals.

Products Mentioned In This Article:

For the full Kikusui Electronic Load range please see HERE

Blown Fuse Testing Precautions When Using Electronic Load

This article will address some precautions on the blown fuse testing such as the unit testing or cable and fuse testing (see Figure 1) and fuse component testing.
1. Test System
A DC power supply, cable, fuse and electronic load are connected as shown in Figure 1.
1) Prepare a DC power supply whose current and voltage capacity are greater than a test range.
2) Set an electronic load to CC mode and set a test current from an electronic load panel.
3) DC power supply: Turn the output on. Electronic load: Turn the load on.
4) Monitor a current with an electronic load ammeter. In general, an electronic load ammeter is more accurate than that of power supply.

Fig. 1
2. Precautions
1) Cable inductance may cause oscillations on electronic loads, especially using longer cables. To prevent it, lower the response speed (RESPONSE) of electronic load (Example for PLZ-4W Series: set RESPONSE to 1/10).
2) If the oscillations persist longer even after lowering the response speed, place an electrolytic capacitor (C = approx. 1000μF) on input terminals of electronic load as shown in Figure 1.
3) Electronic loads can also dynamically change a current (E.g. 0.5A-5A, Duty: 30%, at 200HZ). The rise and fall times vary with the response setting and slew rate setting.

Products Mentioned In This Article:

Kikusui’s full range of DC Power Supplies and Electronic Loads please see HERE

How to Measure Output Impedance of Power Supply with Bipolar Power Supply PBZ SeriesPBZ

Series is a bipolar power supply that can be also operated in quadrant 2 to sink the current. This function enables you to measures an output impedance of DUT (e.g. fuel cell, DC power supply) by using PBZ Series as an electronic load. PBZ Series equips with an AC waveform generation function so that you do not need to prepare another oscillator.
The following procedures explain how to flow the load current of DC5A and AC1Arms (1 kHz) to DUT power supply. To accurately measure the impedance, an AC voltmeter and AC ammeter are required.

<Procedures>
1) Reset PBZ to the factory default, if needed. SHIFT+POWER ON
2) Set PBZ to the constant current (CC) mode. Press the CONFIG key (menu page 1/7). MODE
POLARITY: BIPOLAR/UNIPOLAR *Press▼ to move the cursor. Turn the knob to specify the setting. CONTROL: CC
3) Set a DC current on PBZ.
Press the DC key.
DC -5.000A (Note: Negative current should be set.)
4) Set an AC current on PBZ. Press the AC key. FUNC Sine wave
AMPL 2.8 A p-p (AC will flow at 1Arms.) FREQ 1000.00Hz (1 kHz)
AC ON
5) Turn DUT’s output on.
After checking that the negative voltage is applied on the PBZ COM terminal and the positive voltage is applied on the PBZ OUT terminal, turn DUT’s output on.
6) Turn PBZ’s OUTPUT on.
PBZ will sink the current from DUT.
7) Check the current.
Press the MEASURE key.
FUNC DC : Measure DC current/voltage *Turn the knob. FUNC AC : Measure AC current/voltage
8) Turn PBZ and DUT off.
Turn PBZ’s OUTPUT off. Then, Turn DUT’s output off.
Please be noted that the negative voltage might be applied to the DUT by wrong procedures. If the DUT has a diode in parallel with the output, it will be protected that the sink current flows through the diode.

Products Mentioned In This Article:

• PBZ Series please see HERE

1. Test Condition

: Conduct the vibration testing on the automotive wiring harness connector under supplied at 12 VDC/1 A.
2. Test Criteria: If the resistance of the wiring harness connector exceeds 7.0 Ω for more than 1 microsecond (us),
it defines an electrical discontinuity.
3. Test Circuit:

4. How to Conduct Test

• Calculate the resistance of the wiring harness connector based on the current change using Ohm’s law (measure the current and the time interval with an oscilloscope); E.g. If the current changes from 1.0 A to 0.63 A; it would be approx. 7.0 Ω (excluding the resistance of the connection cables).
• If the connection cables are too long from the DC power supply to the wiring harnesses, place a capacitor at their connecting point to reduce the cable’s inductance.
• Operate the DC power supply in constant voltage (CV) mode. Since the voltage is constant, the current depends on the connector’s contact resistance and the load resistance. So, the connector’s contact resistance can be accurately measured.
• The resistance calculation accuracy is affected by the inductance of the wiring harnesses and the connection cables. To minimize the induction effect, make them into a twisted pair and as short as possible.
• Use a non-inductive resistance for the load resistance (Do not use an electronic load instead, otherwise the current cannot be accurately measured.)
• We recommend you to use a current probe for the current waveform observation. If connecting a resistor to observe the waveform, you may not obtain an accurate measurement especially if the voltage becomes lower due to noise generated from the connector.

Products Mentioned In This Article:

• PMX Series please see HERE

PBZ Series: How to Output Synchronised Square Wave from TRIG OUT Terminal

To transmit a synchronised trigger pulse for output, you can create a trigger signal output (TRIG OUT): through the sequence function or with the following settings. When you output a square wave signal, it is easier to configure the following settings. The settings are available in a single operation only, not in a synchronized operation.
1. Output Example

PBZ outputs at 1 kHz.

2. Settings
Note: Set TRIG OUT to SYNC in the menu page 5/5. See the actual setting examples below:

*1: If SWEEP is set to OFF, set AC signal frequency in the FREQ setting.
*2: You can change the phase of output and trigger signal output (TRIG OUT) in the PHASE setting. *3: If TRIG OUT is set to SYNC, the square wave signal is outputted regardless of the SWEEP
setting.

Products Mentioned In This Article:

• PBZ Series please see HERE