Electrostatic System Checks

Transcription

1 Instruction Sheet P/N Electrostatic System s WARNING: Allow only qualified personnel to perform the following tasks. Follow the safety instructions in this document and all other related documentation. WARNING: Risk of electrical shock. Failure to observe may result in personal injury, death, or equipment damage. WARNING: System or material pressurized. Relieve pressure. Failure to observe this warning may result in serious injury or death. WARNING: Injection. Do not point this device at yourself or other personnel. Failure to observe this warning may result in serious injury or death. 1. Introduction This manual contains common electrostatic checks for a finishing system. These checks consist of measuring resistance of components throughout the system. Perform these checks during installation and at regular intervals for fire safety, electrostatic shock avoidance, and to maintain system transfer efficiency. Setup and follow a regular schedule for maintaining the finishing system within recommended resistance specifications. Your local Nordson representative or distributor can assist you with a recommended checking interval for your specific installation. NOTE: Nordson recommends the use of a 500- or 1000-volt megohm meter for taking resistance measurements.

2 2 Electrostatic System s 2. System Preparation To prepare a finishing system for checking electrostatics, perform the following steps: 1. Turn off the electrostatic power supply. Wait at least three minutes to allow the residual voltage to bleed off the supply. 2. Turn off the spray device mover. 3. Ground the coating material supply and the spray device electrode. 4. Flush the fluid delivery system through the spray device. 5. Relieve coating material and air pressure within the fluid delivery system. 6. Remove the air supply hose from the spray device. 7. Carefully disconnect the electrostatic cable from the electrostatic power supply. Touch the cable conductor (brass tip) to a true earth ground. 8. Clean the outside of the spray device with a compatible cleaning solution.

3 Electrostatic System s 3 3. System ing The electrostatic checks described in this section are not system specific. They provide a framework for verifying resistance measurements on the electrostatic components within a finishing system. NOTE: A diagram illustrates each resistance measurement within the table. Periodic Resistance s Page ÁÁÁÁ ÁÁÁ ÁÁÁ 1. ÁÁÁÁÁÁÁ Electrode of the spray device and electrostatic cable ÁÁÁÁ 4 (if applicable) ÁÁÁ ÁÁÁ 2. ÁÁÁÁÁÁÁ Electrode to the handle or body of the spray device ÁÁÁÁ 4 ÁÁÁ 3. Handle or body of the spray device to true earth 5 ÁÁÁ ground ÁÁÁ ÁÁÁ 4. ÁÁÁÁÁÁÁ High-voltage activator switch of the spray device (If ÁÁÁÁ 5 applicable) ÁÁÁ ÁÁÁ 5. ÁÁÁÁÁÁÁ Resistor of the spray device (If applicable) ÁÁÁÁ 5 ÁÁÁ ÁÁÁ 6. ÁÁÁÁÁÁÁ Electrostatic cable connecting nut to connecting nut ÁÁÁÁ 6 ÁÁÁ 7. Electrostatic cable nut to the brass tip 6 ÁÁÁ ÁÁÁ 8. ÁÁÁÁÁÁÁ Electrostatic cable brass tip to brass tip ÁÁÁÁ 6 ÁÁÁ 9. Electrostatic cable control wires (airless spray-device 7 cables only) ÁÁÁÁ ÁÁÁ ÁÁÁ 10. ÁÁÁÁÁÁÁ Electrostatic power supply well to true earth ground ÁÁÁÁ 7 ÁÁÁ 11. ÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ Electrostatic cable nut to true earth ground 7 Á ÁÁÁ 12. ÁÁÁÁÁÁÁ Bare hand of an operator standing on the work ÁÁÁÁ 8 surface to true earth ground ÁÁÁÁ ÁÁÁ 13. ÁÁÁÁÁÁÁ Coating material supply to true earth ground ÁÁÁÁ 8 ÁÁÁ ÁÁÁ 14. ÁÁÁÁÁÁÁ Substrate to true earth ground ÁÁÁÁ 9 ÁÁÁ 15. ÁÁÁ ÁÁÁÁÁÁÁ ÁÁÁÁ Floor to true earth ground within spray area 9 Á

4 4 Electrostatic System s Resistance Reason for Reading Corrective Action ÁÁ 1. Electrode of the spray deviceááááááá 250 to 375 Make sure the If the combined resistance of ÁÁ and electrostatic cable (if ÁÁÁÁÁÁÁ mega ohms (MΩ) combined resistance the electrode and cable is not applicable) of the spray-device within the specification: ÁÁÁÁÁÁ resistor and the ÁÁÁÁÁÁ electrostatic cable is 1. Remove the cable from ÁÁÁÁÁÁ within the the spray device and recommended perform all remaining ÁÁÁÁÁÁ specification electrostatic cable ÁÁÁÁÁ checks. ÁÁÁÁÁ 2. Remove the resistor from ÁÁÁÁÁ the spray device and ÁÁÁÁÁ check resistance A ÁÁÁÁÁ 3. Clean and inspect the ÁÁÁÁÁ extension. ÁÁÁÁÁ 2. Electrode to the handle or Infinity Ω Make sure that no If you can take a resistance ÁÁ body of the spray device ÁÁÁÁ electrical path exists measurement: ÁÁÁÁÁÁ within the spray ÁÁÁÁÁÁ device that will bypass 1. Disassemble and clean all or part of the the spray device. ÁÁÁÁÁÁ electrical charge to ÁÁÁÁÁÁ ground 2. Replace parts as necessary. ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ A

5 Electrostatic System s 5 Resistance ÁÁÁÁÁÁÁ Reason for Corrective Action Reading ÁÁÁÁÁÁÁ ÁÁ 3. Handle or body of the sprayááááááá 20 Ω, maximum Make sure the If handle to ground ÁÁ device to true earth ground electrostatic cable or resistance is more than a grounding air hose 20 ohms: ÁÁÁÁÁÁÁ provides a path to ÁÁÁÁÁÁÁ ground for the spray 1. all connections. ÁÁÁÁÁÁÁ device 2. electrostatic power ÁÁÁÁÁÁ supply ground. ÁÁÁÁÁÁ 3. air regulator ÁÁÁÁÁÁ ground. ÁÁÁÁÁÁ POWER UNIT ÁÁÁÁÁÁ 4. Replace parts as ÁÁÁÁÁÁ necessary A ÁÁÁÁÁÁ NOTE: When applicable, ÁÁÁÁÁÁ take resistance reading with ÁÁÁÁÁÁ the cable connected between the spray device and the ÁÁÁÁÁÁ electrostatic power supply. ÁÁÁÁÁÁ Otherwise, take resistance ÁÁÁÁÁÁ reading with a grounding air hose connected between the ÁÁÁÁÁÁ spray device and its ÁÁÁÁÁÁ grounded air regulator. ÁÁÁÁÁÁ 4. High-voltage activator switch 0 Ω ; trigger Make sure the switch If the switch resistance is not ÁÁ of the spray device (If depressed, activates the high within the specification, ÁÁ applicable) InfinityΩ; trigger voltage from the realign or replace as released electrostatic power necessary. supply ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ A ÁÁÁÁÁÁ ÁÁ 5. Resistor of the spray deviceááááááá 10% of the Make sure If the resistance (If applicable) resistance value spray-device resistor measurement is not within stamped on side is within specification specification, replace the of resistor ÁÁÁÁÁÁÁ resistor. ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁ A ÁÁÁÁÁÁÁ

6 6 Electrostatic System s Resistance ÁÁÁÁÁÁÁ Reason for Corrective Action Reading ÁÁÁÁÁÁÁ ÁÁ 6. Electrostatic cable ÁÁÁÁÁÁÁ 20 Ω maximum Make sure the sheath If the cable nut to nut ÁÁ connecting nut to connectingáááá of the cable provides resistance is greater than nut a path to ground for 20 ohms: ÁÁÁÁÁÁ the spray device ÁÁÁÁÁ 1. cable nut connections. ÁÁÁÁÁ ÁÁÁÁÁ 2. Replace worn or ÁÁÁÁÁ damaged cable. ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ A ÁÁÁÁÁ ÁÁ 7. Electrostatic cable nut to the ÁÁÁÁÁÁÁ Infinity Ω Make sure electrical If a path exists between the brass tip isolation exists center conductor and the ÁÁÁÁÁÁ between the cable sheath, replace the cable. ÁÁÁÁÁÁ sheath (cable nut) and ÁÁÁÁÁÁ the center conductor (brass tip) ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁ A ÁÁÁÁ ÁÁ 8. Electrostatic cable brass tip ÁÁÁÁÁÁÁ 163 to 245 MΩ Make sure the If the cable resistance is not ÁÁ to brass tip ÁÁÁÁ electrostatic cable within specification, replace provides the proper the cable. ÁÁÁÁÁÁ current-limiting ÁÁÁÁÁÁ resistance (brass tip ÁÁÁÁÁÁ to brass tip) ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ A

7 Electrostatic System s 7 Resistance ÁÁÁÁÁÁÁ Reason for Corrective Action Reading ÁÁÁÁÁÁÁ ÁÁ 9. Electrostatic cable control ÁÁÁÁÁÁÁ 0 Ω, 1 to 1A; Make sure each If wire resistance is not within ÁÁ wires (airless spray-device 0 Ω, 2 to 2A; control wire does not specification: cables only) contain breaks and Infinity Ω, 1 to 2; their electrically 1. Look for breaks or Infinity Ω,1 to isolated from the missing insulation in each cable nut; cable sheath control wire. Repair wire if possible. ÁÁ 1A Infinity Ω ; 2 to ÁÁÁÁÁÁÁ cable nut. 2A ÁÁ 1 2ÁÁÁÁÁ 2. Replace defective cable. ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ A ÁÁÁÁÁÁ ÁÁ 10. Electrostatic power-supply 0 Ω Make sure the If resistance measurement is well to true earth ground electrostatic power greater than zero ohms, ÁÁÁÁÁÁÁ supply is connected to check power unit grounding ÁÁÁÁÁÁÁ true earth ground device. ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁÁÁÁÁ ÁÁ POWER UNIT ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ A ÁÁÁÁÁÁ ÁÁ 11. Electrostatic cable nut to 0 Ω Make sure the If the resistance true earth ground electrostatic cable has measurement is greater than ÁÁÁÁÁÁÁ a good connection to 0 ohms: ÁÁÁÁÁÁÁ the electrostatic power supply 1. Tighten cable connection ÁÁÁÁÁÁ at the electrostatic power ÁÁÁÁÁÁ supply. ÁÁÁÁÁÁ 2. Look for a poor ÁÁÁÁÁÁ connection between the POWER UNIT ÁÁÁÁÁÁ cable nut and sheath. ÁÁ A ÁÁÁÁÁÁÁ Replace electrostatic cable. ÁÁÁÁÁÁ ÁÁÁÁÁÁ NOTE: Take resistance ÁÁÁÁÁÁ reading with the cable connected to the electrostatic ÁÁÁÁÁÁ power supply.

8 8 Electrostatic System s Resistance ÁÁÁÁÁÁÁ Reason for Corrective Action Reading ÁÁÁÁÁÁÁ ÁÁ 12. Bare hand of an operator ÁÁÁÁÁÁÁ Less than 50 MΩ Make sure static If resistance is greater than ÁÁ standing on the work surface ÁÁÁÁÁÁÁ (recommended) charge does not 50 megaohms: to true earth ground accumulate on ÁÁÁÁÁÁ operating personnel 1. shoes (soles must ÁÁÁÁÁÁ within the spray area, be made of conductive ÁÁÁÁÁÁ avoid electrostatic materials). shock, and for fire ÁÁÁÁÁÁ safety 2. Provide additional ÁÁÁÁÁ grounding devices for example shoe straps, ÁÁÁÁÁ wrist strap. ÁÁÁÁÁ ÁÁÁÁÁ 3. for accumulated A ÁÁÁÁÁ coating material residue on the floor of the booth. ÁÁÁÁÁ Clean floor as appropriate ÁÁÁÁÁ ÁÁÁÁÁ NOTE: As the operator stands or walks on the usual ÁÁÁÁÁ work surface in the spray ÁÁÁÁÁ area, take resistance reading ÁÁÁÁÁ from the bare hand of the operator to true earth ground. ÁÁÁÁÁ ÁÁ 13. Coating material supply to ÁÁÁÁÁÁÁ 0 Ω Make sure all If resistance measurement is true earth ground components within the greater than 0 ohms, add ÁÁÁÁÁ spray area are at true additional grounding devices ÁÁÁÁÁÁ earth ground potential to the coating material ÁÁÁÁÁÁ to prevent static supply. charge buildup ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁÁÁÁ ÁÁ A ÁÁÁÁ

9 Electrostatic System s 9 Resistance ÁÁÁÁÁÁÁ Reason for Corrective Action Reading ÁÁÁÁÁÁÁ ÁÁ 14. Substrate to true earth ÁÁÁÁÁÁÁ Less than 200 Ω Make sure a path to If resistance measurement is ÁÁ ground recommended true earth ground greater than 200 ohms, clean exists to prevent the hooks, hangers, and ÁÁÁÁÁÁÁ part from building up conveyors. ÁÁÁÁÁÁÁ an electrostatic ÁÁÁÁÁÁÁ charge NOTE: For a resistance measurement greater than ÁÁÁÁÁÁ 1 M, corrective action is ÁÁÁÁÁÁ necessary. ÁÁÁÁÁÁ ÁÁ A ÁÁÁÁÁÁÁ ÁÁÁÁÁÁ 15. Floor to true earth ground 0 Ω, for metal Make sure a path to Clean grating or make ÁÁ within spray area floors; Less than true ground exists to provision for the operator 50 MΩ, for prevent static charge grounding. non-metal floors build-up on the ÁÁÁÁÁÁÁ operator NOTE: For booth floors ÁÁÁÁÁÁ constructed of materials other than metal, it may be ÁÁÁÁÁÁ necessary to puddle a small ÁÁÁÁÁÁ amount of tap water on the ÁÁÁÁÁÁ floor to provide an electrical connection for the meter ÁÁÁÁÁÁ probe. ÁÁÁÁÁÁ A ÁÁÁÁÁÁ

10 10 Electrostatic System s Original copyright date Nordson and the Nordson logo are registered trademarks of Nordson Corporation.