UNI-T UT-P40 AC DC Current Probe Instruction Manual

: June 5, 2024
: UNI-T

Table of Contents

UNI-T UT-P40 AC DC Current Probe
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UNI-T UT-P40 AC DC Current Probe

General Safety Instructions:
Read the following safety instructions to avoid injury and prevent damage to this product or any products connected to it. Use this product only as specified. Only qualified personnel should perform service procedures.

To Avoid Fire or Personal Injury Connect and Disconnect Properly.
Connect the probe output to the measurement instrument before connecting the probe to the circuit under test. Disconnect the probe input and the probe ground from the circuit under test before disconnecting the probe from the measurement Instrument.

Observe All Terminal Ratings.
To avoid fire or shock hazard, observe all rating and markings on the product. Consult the instruction manual for further ratings information before making connections to the product.

Replace Batteries Properly.
Replace batteries only with the proper type and rating specified.

Do Not Operate Without Covers.
Do not operate this product without the covers or panels.

Avoid Exposed Circuitry.
Do not touch exposed connections and components when power is present.

Do Not Operate With Suspected Failures.
If you suspect there is damage to this product, have it inspected by qualified service personnel.

Do Not Operate in Wet/Damp Conditions. Do Not Operate in an Explosive Atmosphere. Keep Product Surfaces Clean and Dry.

Safety Terms and Symbols:

Terms in This Manual.
These terms may appear in this manual.

Warning statements identify conditions or practices that could result in injury or loss of life.

Caution statements identify conditions or practices that could result in damage to this product or other property.

Terms on the Product.
These terms may appear on the product.

DANGER: Indicates an injury hazard immediately accessible as you read the marking.

WARNING: indicates an injury hazard not immediately accessible as you read the marking.
CAUTION: Indicates a hazard to property including the product.

Symbols on the Product.
These symbols may appear on the product: Attention refer to operation Instructions.
This instrument has double insulation.

Getting Started:

The current probe enables a general purpose oscilloscope to display AC and DC current signals up to 30 amps Peak (21A RMS). The current probe can also make AC and DC measurements with a multimeter by using the recommended accessory MT-246N (BNC-to-banana) plug adapter.

PIC 1

Output Into
Press Button
Battery Cover
Test Position Max. 11Wire
DC Zero Offset
Range Selection (Power On/Off)

Shows the controls and indicators on the

Control/Indicator	Description
Current flow symbol. The arrow shows the probe’s polarity convention

for measuring current flowing from positive to negative.
| ****

| | Zero adjustment. Rotate to adjust the probe output to zero when there is no current present. It may also be used to offset a DC signal component. Zeroing is not needed for AC measurements unless your instrument cannot isolate a DC component (if present).
| | OFF/Range switch. Slide the switch from OFF to either the 5 mV/A or 50mV/A range. When either range is selected, the probe is turned on, and the green battery indicator lights. If the indicator does not light, see Battery Notes and Battery Installation.
**| Battery indicator.** The green battery indicator lights when the probe is turned on. For more information, see Battery Notes and Battery Installation .

| Overload indicator. The red overload indicator lights if the measured signal is greater than the selected range capacity.
Switch the probe to 5 mV/A if possible, or remove the probe from the circuit.

These characteristics apply to an adjusted UT-P40 AC/DC Current Probe installed on an oscilloscope of any brand. The oscilloscope must be warmed up for at least 20 minutes and be in an environment with the temperature at 10~30 and the humidity at 0~80.

Size	231 mm x67 mm x 36 mm
Maximum Conductor	10.3 mm
Cable Length	200 cm
Weight	310 g (without battery)

Environmental Characteristics

Temperature	0°C to +50°C
(+32°F to +122°F)
Storage temperature	-20°C to +80°C (-4°F to +176°F)
Humidity	0°C to 40°C, 95% humidity 40°C to 50°C, 45% humidity
Pollution Degree	2

Basic Operation:
Before using the probe, the batteries must be installed.

WARNING!
Do not clamp the probe onto circuits with voltages greater than 600 VAC. Personal injury or damage to the probe may result. Always connect the UT-P40 current probe output to the instrument before clamping onto the circuit under test.

First connect the current probe BNC connector to BP-250 (double BNC connection cable) then connect to oscilloscope input. Start by setting the oscilloscope voltage input channel to DC volts, and the voltage sensitivity scale to 5m V/div.
Move the OFF/ Range switch to the 5 mV/A or 50 mV/A position to turn on the probe. (The UT-P40 current probe has a green LED power/battery indicator. If the LED does not light, replace the battery or use specified power adaptor.)
Use the ZERO adjustment to zero or offset the probe output detection of residual magnetic DC charges.
Connect the probe to the circuit by opening the jaws and clamping around the conductor. See Figure 2.
NOTE. Clamping around both the “hot” and neutral wires may give you a zero reading. (Remember to unclamp the probe from the conductor before disconnecting it from your meter or instrument).
Adjust the probe channel and oscilloscope’s time base as necessary to get a clear and stable view of the signal. Set the oscilloscope input to DC volts to see both the AC and DC currents; set the channel to AC to see the AC current only.
The current drawn by different devices look much different than that of others. While the RMS current can only be used in low frequency current, the momentary peaks may be quite high. Figure 3 shows the difference between the line current drawn by a resistive load and a motor controller.
Congratulations on your purchase of the UT-P40, a multifunctional current probe. When connecting to a digital meter, use the recommended MT-246N (BNC-to-banana adapter). Connect the black lead to the meter COM (black letters on the meter), and the red lead to the V input (red letters on the meter).
To measure only AC current, set the meter to measure AC volts.
To measure DC current, set the meter to measure DC volts. Note the current convention arrow on the probe to get the proper polarity reading.
To increase the measurement sensitivity of the UT-P40 current probe, loop additional turns of the wire under test through the jaws. See Figure 4. The sensitivity of the UT-P40 current probe is multiplied times the number of loops in the jaws. For example: 50mV/A X5turns=250mV/A

Electrical Characteristics

Current Range	5mV/A ; 50mV/A
DC Accuracy, typical	±2% ±0.4A at 50mV/A

Voltage and current ratings

| Maximum working current(A)| Maximum Working voltage (V)| Maximum floating voltage (V)
---|---|---|---
Rating| Range
5mV/A| Range
50mV/A| Maximum Working voltage (V)| Maximum floating voltage (V)
DC| 30| 5| 600| 600
DC +peak AC| 30| 5| 600| 600
AC peak| 30| 5| 600| 600
AC