AC power supply PCR-LE series

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Using the Voltage compensation Function

The compensation function compensates for voltage drops in the load cables when the load is connected to the PCR-LE Series over a long distance. The PCR-LE Series has three types of compensation functions: soft sensing, hard sensing, and regulation adjustment. Use the different compensation functions depending on how you need to use the PCR-LE Series.

Wiring the hard sensing and soft sensing functions

Compensation function setup procedure

Checking the sensing functions (excluding the regulation adjustment function)

During single-phase, three-wire output and three-phase output (optional), regulation adjustment is invalid.

58389.jpg WARNING

Risk of electric shock.

Before you connect the load or the sensing cables, turn the POWER switch off, and then remove the power plug from the outlet or turn off the switchboard.

Firmly attach the terminal box cover.

Hard sensing

Connect the PCR-LE’s internal output voltage compensation point directly across the load. Because compensation is performed in real time, the output voltage can be stabilized at a high speed.

Because the impedance (the combination of the resistance and the inductance) of the power line across the load will be included in the compensation circuit, the power circuit’s stability decreases. The PCR-LE Series operations may become unstable (for example, it may oscillate) depending on the wiring and the load type. If the operations become unstable, use soft sensing.

It is recommended that you use soft sensing if you are using a load that does not require a fast output voltage response speed.

You cannot use hard sensing in the following situations.

When the output is on

When you are setting the output impedance (ON)

When you have selected the normal response speed (MEDIUM) or the fast response speed (FAST).

Soft sensing

The voltage of the sensing point is measured by the PCR-LE Series measurement functions, and any insufficiencies in the voltage are automatically compensated for. The performance of the PCR-LE Series such as the stability of the voltage, output voltage response to sudden changes in the load current, and waveform quality (distortion ratio) is lower than that available during normal operation.

Even in DC mode, the performance is lower than that available during remote sensing of a normal DC power supply.

The maximum voltage that soft sensing can compensate is “the PCR-LE Series’ output voltage + 10 %.” The maximum output voltage during compensation is limited by the rated voltage of the PCR-LE Series.

You cannot use soft sensing in the following situations.

When the output is on

When in AC+DC mode

When you are setting the output impedance (ON)

When you have configured the PCR-LE Series so that it does not turn output off when the current limit is exceeded (DISABLE)

When you have specified the waveform bank

When power line abnormality simulations are being performed

When sequences are being performed

When soft start is on.

Regulation adjustment

This function calculates the voltage drops that are caused by the output current and increases the output voltage just by the calculated voltage drops.

Use this function when there is a great distance between the PCR-LE Series and the load and you want to stabilize the voltage across the load. This function does not require you to connect the sensing cables that the hard sensing and soft sensing functions require.

The performance of the stabilization accuracy, distortion ratio, and response speed of the voltage is lower than the normal performance of the PCR-LE Series. Depending on how you are using the PCR-LE Series, you may not be able to use this function. Check the operation that you will perform before you use the regulation adjustment function.

The maximum voltage that regulation adjustment can compensate is “the PCR-LE Series’ output voltage + 10 %.” The maximum output voltage during compensation is limited by the rated voltage of the PCR-LE Series. If the output current is 10 % or less of the maximum rated current, the voltage is not compensated.

You cannot use regulation adjustment in the following situations.

When the output is on

When in AC+DC mode, in DC mode

When you are setting the output impedance (ON)

When you have configured the PCR-LE Series so that it does not turn output off when the current limit is exceeded (DISABLE)

When you have specified the waveform bank

When power line abnormality simulations are being performed

When sequences are being performed

When soft start is on.

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Wiring the hard sensing and soft sensing functions

Twist the load wires (L and N), and connect between the output terminal and load with the shortest wires possible. If you cannot twist the wires, we recommend that you run the wires alongside each other and tie them together at several points with cable ties.

The sensing feature can compensate up to 1.5 V for a single line. Select a load cable that has sufficient current capacity to prevent the voltage drop in the cable from exceeding the compensation voltage.

As the PCR-LE Series output voltage becomes small, so too does the detected voltage. If the PCR-LE Series output voltage is small, reduce the voltage drops in the cables by using cables that have large diameters to wire the load, connecting the load so that the cables are as short as possible, and taking other similar precautions.

58381.jpg CAUTION

Risk of damage to the product and the load. If the sensing cables become disconnected or the polarities are incorrect, an overvoltage will be generated in the output. The protection function will be activated and the output will be turned off, but an overvoltage will be generated for the several hundreds of milliseconds before the protection function is activated.

Pull out the terminal block tray, and then connect the sensing cables.

Use AWG22 to AWG16 cables when connecting to the sensing terminals. Strip approximately 10 mm of coating from the end of the cables.

Match the N and L of the OUTPUT terminal block and N and L of the SENSING terminal block.

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1

Check that the POWER switch is turned off.

2

Check that the load’s power switch is off.

If you cannot turn the load off, install a dedicated terminal block for sensing. Do not connect the load to this dedicated terminal block for sensing.

3

Connect the N SENSING terminal to the N terminal on the DUT using sensing cables. In the same way, connect the L SENSING terminal to the L terminal on the DUT.

Connect the wiring so that the product is as close to the load as possible.

Using the Voltage compensation Function (Cont.)

Wiring the hard sensing and soft sensing functions (Cont.)

Wiring for single-phase three-wire output or three-phase output (optional)

Single-phase three-wire output

Connect the output wires of each phase (L and N) to the load (sensing point).

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Three-phase output (Three-phase four-wire)

Connect the output wires of each phase (L and N) to the load (sensing point).

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Three-phase output (Three-phase three-wire)

The stability of three-phase three-wire output voltage decreases for unbalanced loads. Unstable operation may result with hard sensing.

Make the connection between the PCR-LE series N OUTPUT terminal and N SENSING terminal as short as possible. Connect all N terminals to the center PCR-LE.

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Wiring the regulation adjustment function

After you finish connecting the load, turn the output on. Then, set the output voltage to the voltage that is required across the load. Because of voltage drops in the load wiring, the voltage across the load is lower than the voltage generated by the PCR-LE Series. Use a voltmeter (or other instrument that enables you to measure voltage) to check whether the voltage across the load is the required voltage.

The maximum voltage that regulation adjustment can compensate is “the PCR-LE Series’ output voltage + 10 %.”

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Compensation function setup procedure

Set the voltage and the frequency that you want to stabilize at the sensing point. In DC mode, set only the voltage.

Press OTHER (SHIFT+MEMORY), 1/2 (F6), and then COMPEN (F2) to configure the compensation functions.

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Item

Title

Description

Conditions in which the function key cannot be used

Valid modes

OFF

Compensation

The compensation (voltage compensation) functions are not used.

None

All

SENS.-H

The hard sensing function is used.

Output: on

Output impedance: setting

Response: MEDIUM or FAST

SENS.-S

The soft sensing function is used.

You cannot change the output voltage while the soft sensing function is in use. Set the voltage before you enable the soft sensing function.

Output: on

Output impedance: setting

Action to perform when the current limit is exceeded: DISABLE

Waveform bank: specified

Soft start: on

Power supply line error simulation: being performed

Sequence: being performed

AC and DC

REG ADJ*1

The regulation adjustment function is used.

Allow a current to flow through the load. Then, check the voltmeter that is attached across the load, and use the rotary knob to adjust the PCR-LE Series voltage to the same value that is displayed.

AC

*1. Not valid in single-phase three-wire output and three-phase output (optional)

Adjusting the regulation adjustment function

Press OTHER (SHIFT+MEMORY), 1/2 (F6), and then COMPEN (F2) to select REG ADJ (F4). After you have selected the regulation adjustment function, you have to adjust it.

Allow a current to flow through the load. Then, check the voltmeter that is attached across the load, and use the rotary knob to adjust the PCR-LE Series voltage to the same value that is displayed.

After you have finished adjusting the function, press ESC to return to the home position.

Using the Voltage compensation Function (Cont.)

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Checking the sensing functions (excluding the regulation adjustment function)

When you are using the hard sensing function or soft sensing function, after you finish wiring the sensing cables, check that there are no wiring errors. Turn the load’s power switch off before you perform this check.

1

Turn the POWER switch on.

2

Set the output undervoltage protection (UVP) to 5 V.

3

Set the output overvoltage protection (OVP) to 20 V.

4

Set the output voltage range to the H range.

5

Set the output voltage to 10 V, and then turn the output on.

6

Check whether a voltage of several tens of volts is being generated.

An output being generated in this situation indicates that there are connection errors. Check whether the sensing cables are connected and whether the polarities are correct. If the sensing cables are disconnected or the polarities are incorrect, a voltage will be applied across the load (at the sensing point) for approximately one second until the protection function is activated.

If the sensing cables are not firmly connected, an alarm (ALM-07: UVP) may be generated. If the polarities of the sensing cables are not correct, an alarm (ALM-00: OVP) may be generated. Connect the cables correctly.

If you are installing a dedicated terminal block for sensing, check the sensing function before you connect the load to the terminal block.

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