1. Introduction
This manual provides essential instructions for the safe and effective use of the Fluke 1535 Insulation Tester. The Fluke 1535 is designed for frontline troubleshooting in industrial and electrical environments, including solar installations. It offers user-selectable test voltages from 250 V to 2500 V and resistance measurements up to 500 GΩ, enabling a wide range of testing applications.
What's in the Box:
- Fluke 1535 Insulation Tester
- TL1550B Test Lead Set
- Carrying Case
Figure 1.1: Fluke 1535 Insulation Tester with its test lead set and carrying case.
2. Safety Information
Always adhere to local and national safety codes. Use the tester only as specified in this manual; otherwise, the protection provided by the tester may be impaired. Read the entire manual before use. Pay close attention to all warnings and cautions.
- Electrical Shock Hazard: High voltages are present during insulation testing. Exercise extreme caution.
- Personal Protective Equipment (PPE): Always wear appropriate PPE, including insulated gloves and safety glasses, when working with electrical systems.
- CAT IV 600V Rating: The Fluke 1535 complies with CAT IV 600V standards, indicating its suitability for measurements at the source of the low-voltage installation. However, always verify the voltage rating of the circuit before testing.
- Inspect Test Leads: Before each use, inspect test leads for damage to insulation or exposed metal. Replace damaged leads immediately.
- Do Not Operate in Wet Conditions: Do not use the tester in wet environments or if the device itself is wet.
- Battery Safety: Ensure batteries are correctly installed and replace them when the low battery indicator appears.
3. Product Overview
The Fluke 1535 Insulation Tester is a robust tool designed for efficient and accurate insulation resistance measurements. Its key features include:
- Quick and efficient determination of the integrity of cables, motor windings, transformers, and other electrical equipment.
- Automatic calculation of Polarization Index (PI) and Dielectric Absorption Ratio (DAR).
- Fast and stable resistance readings for higher efficiency.
- Integrated voltage alarm function for enhanced safety.
Figure 3.1: Front view of the Fluke 1535 Insulation Tester.
Figure 3.2: Test Lead Input Terminals (E, G, L).
Figure 3.3: Control Buttons (Power, Function, Test, Test Volts, Backlight).
4. Setup
4.1 Battery Installation
The Fluke 1535 is battery-powered. Refer to the battery compartment cover on the back of the unit for instructions on installing or replacing batteries. Ensure correct polarity.
4.2 Connecting Test Leads
- Ensure the tester is powered off before connecting leads.
- Connect the red test lead to the L (Line) terminal.
- Connect the green test lead to the G (Guard) terminal (if using a guard connection).
- Connect the black test lead to the E (Earth) terminal.
- Ensure all connections are secure.
5. Operating Instructions
5.1 Powering On/Off
Press the Power button to turn the tester on or off.
5.2 Selecting Test Voltage
Use the TEST VOLTS button to cycle through available test voltages (250 V, 500 V, 1000 V, 2500 V). Select the appropriate voltage for your application based on equipment specifications and safety standards.
5.3 Performing an Insulation Resistance Test
- Ensure the circuit under test is de-energized and locked out according to safety procedures.
- Connect the test leads to the circuit or component.
- Select the desired test voltage using the TEST VOLTS button.
- Press and hold the TEST button to initiate the insulation test. The display will show the applied voltage and the measured resistance.
- Release the TEST button to stop the test. The measured resistance will remain on the display.
- Allow the circuit to discharge completely before disconnecting the test leads.
Figure 5.1: Performing an insulation resistance test in an industrial setting.
5.4 Polarization Index (PI) and Dielectric Absorption Ratio (DAR)
The Fluke 1535 automatically calculates PI and DAR, which are crucial for assessing the condition of insulation over time. These ratios help identify moisture or contamination in insulation.
- DAR: Ratio of insulation resistance at 60 seconds to insulation resistance at 30 seconds.
- PI: Ratio of insulation resistance at 10 minutes to insulation resistance at 1 minute.
To perform a PI or DAR test, select the appropriate function using the FUNCTION button and then press the TEST button. The tester will automatically perform the timed measurements and display the calculated ratio.
6. Maintenance
6.1 Cleaning
Wipe the case with a damp cloth and mild detergent. Do not use abrasives or solvents. Ensure the tester is completely dry before use.
6.2 Battery Replacement
When the low battery indicator appears on the display, replace the batteries promptly to ensure accurate measurements. Refer to the battery compartment for specific battery type and replacement instructions.
6.3 Storage
Store the tester and its accessories in the provided carrying case in a dry, cool environment, away from direct sunlight and extreme temperatures.
7. Troubleshooting
| Problem | Possible Cause | Solution |
|---|---|---|
| Tester does not power on. | Dead or incorrectly installed batteries. | Check battery installation; replace batteries. |
| No reading or "OL" (Overload) displayed during test. | Open circuit, very high resistance, or incorrect test lead connection. | Verify test lead connections; ensure circuit is closed; check for breaks in insulation. |
| Inconsistent or fluctuating readings. | Poor test lead contact, external interference, or unstable test environment. | Ensure firm contact with test points; minimize external electrical noise; re-test in a stable environment. |
| Voltage alarm activates unexpectedly. | Residual voltage in the circuit or circuit is not fully de-energized. | Ensure the circuit is completely de-energized and discharged before testing. |
If problems persist, contact Fluke customer support or an authorized service center.
8. Specifications
| Feature | Detail |
|---|---|
| Model Number | FLUKE-1535 |
| Test Voltages | 250 V, 500 V, 1000 V, 2500 V (user selectable) |
| Resistance Measurement Range | Up to 500 GΩ |
| Safety Rating | CAT IV 600V |
| Automatic Calculations | Polarization Index (PI), Dielectric Absorption Ratio (DAR) |
| Power Source | Battery Powered |
| Product Dimensions | 7.3 x 8.3 x 3.7 inches |
| Item Weight | 6.1 Pounds (approximately 2.76 kg) |
| Color | Yellow |
| Manufacturer | Fluke Corporation |
9. Warranty and Support
Fluke products are known for their reliability and quality. For detailed warranty information, please refer to the warranty card included with your product or visit the official Fluke website. For technical support, service, or calibration, contact Fluke customer service or an authorized Fluke service center.
Official Fluke Website: www.fluke.com
Figure 9.1: Information on purchasing genuine Fluke products from authorized distributors.
