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© 2013 Belden Inc. | Belden Confidential Peter Cox P.Eng. Project Manager Belden Industrial Cable Best Practices for VFD Cabling.

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Presentation on theme: "© 2013 Belden Inc. | Belden Confidential Peter Cox P.Eng. Project Manager Belden Industrial Cable Best Practices for VFD Cabling."— Presentation transcript:

1 © 2013 Belden Inc. | Belden Confidential Peter Cox P.Eng. Project Manager Belden Industrial Cable Best Practices for VFD Cabling

2 © 2013 Belden Inc. | 2 Belden Confidential Peter Cox Bio Licensed Professional Engineer Worked in or as a consultant to Industry for 28yrs – mostly in a Drives and Industrials Controls Participated in the testing of the first VFD cables developed with a major drive manufacturer in 1995 Did Beta testing of the 1336 Impact drive at Belden

3 © 2013 Belden Inc. | 3 Belden Confidential Learning Objectives Understand Beldens VFD Product Line Belden Premium VFD Belden CTC Construction Grade VFD Understand the 4 Reasons to Specify VFD Cable Common Mode Current Capacitive Coupling/Cable Charging Reflected Wave Voltage Safety and Reliability Discussion of Paralleling

4 © 2013 Belden Inc. | 4 Belden Confidential There is no standard for VFD cables Performance is all about Copper One thing you need to Remember…..

5 © 2013 Belden Inc. | 5 VFD Cable Connects Motor and Drive Power Circuit Provides Reliable and Robust Connection Protects against harmful noise

6 © 2013 Belden Inc. | 6 6 Belden VFD Cable Product Offering Classic Foil/Braid Design VFD Classic Cables Four Conductor Foil / Braid Shield Design VFD Cables (Three stranded TC Conductors + 1 Insulated Ground – green with a yellow stripe) 29500: 16 AWG VFD 29501: 14 AWG VFD 29502: 12 AWG VFD 29503: 10 AWG VFD 29504: 8 AWG VFD 29505: 6 AWG VFD 29506: 4 AWG VFD 29507: 2 AWG VFD More Info in NP 235 Advantages – This construction offers thicker insulation for better performance and extended transmission distance Other Designs – Interlocked Aluminum and Steel armored VFD products (part numbers available in NP316) Much More Copper than 3C designs – Compared to Construction Grade these cables have as much as 3 times the copper at ground potential. Nearly as much as is in the circuit conductors When comparing, look at product weights.

7 © 2013 Belden Inc. | 7 7 Belden VFD Cable Product Offering Symmetrical Design VFD Classic Cables Symmetrical Design VFD Cables (Three stranded TC Conductors + 3 Symmetrical BC Grounds + 2 Spiral Copper Tape Shields) 29528: 1 AWG VFD 29529: 1/0 AWG VFD 29530: 2/0 AWG VFD 29531: 3/0 AWG VFD 29532: 4/0 AWG VFD 29533: 250 AWG VFD (2KV) 29534: 350 AWG VFD (2KV) 29535: 500 AWG VFD (2KV) More Info in NP 235 Advantages – The symmetrical ground design provides a balanced grounding system that is preferred in the industry on larger HP drives Other Designs – Interlocked Aluminum and Steel armored VFD products (part numbers available in NP316) We use 2 copper tapes with twice the surface area for better high frequency conduction. Contra helically applied where possible for lower inductance and higher performance. Much more effective and more expensive than a single tape used on all other products.

8 © 2013 Belden Inc. | 8 © 2012 Belden Inc. | | Page 8 Application Issues Challenges Common Mode Current Capacitive Coupling and Cable Charging Reflected Wave Voltage – Motor and Cable Life Application Reliability and Safety Requirements Reliability - high MTBF Manufacture recommendations Resistance to harsh environment NEC There it NO STANDARD FOR VFD cables Customer Drivers Energy Savings Low Total Cost of Ownership High Availability Safety: People & Processes Belden Quality and higher MTBF components in the industry. The only product in the market that was co-designed in conjunction with a major drives manufacturer Global availability 17 years as a leading supplier of VFD cable

9 © 2013 Belden Inc. | 9 © 2012 Belden Inc. | | Page 9 Application Issues Common Mode Current AKA Current Noise Effects Network Errors - Encoder Faults Loss of signal reliability analog and digital signal error Ground plan noise pollution Motor bearing failures False stops and safety circuit trips and alarms EMI and RFI Mitigation Lowest Impedance ground path and Shielding Make the cable the most attractive path for HF currents High Surface area (4-8x) Conductors reduce HF cable heating and reject less CMC Definition Current that flows between the drive and motor by any path other than the 3 primary motor leads Kirchhoffs Law – The sum of current at any point is zero - All current must return to the drive somehow Why Belden We put up to 3 times more copper at ground potential than competitors VFD cables – with flexible stranding we contain CMC 300% better on our premium VFD Combination of foil braid, or 2 layers of CU enhances performance

10 © 2013 Belden Inc. | 10 Belden Confidential What Does Common Mode Noise Look Like?

11 © 2013 Belden Inc. | 11 Motor Bearing Currents 11 High Voltage can also discharge through the bearings causing etching in the races and premature motor failure

12 © 2013 Belden Inc. | 12 © 2012 Belden Inc. | | Page 12 Application Issues Capacitive - Coupling Cable Charging Effects Loss of motor torque or stalling False trips of drive overcurrent reduced system efficiency Charging of DE energized adjacent circuits Human safety issues Mitigation Lowest Capacitance 150ma/kft /conductor for THHN vs. 50ma/kft/conductor for Belden VFD cable Shielding to prevent interaction between systems Definition Current that leaves the drive but is lost due to capacitive interaction with other cables. (Cable Charging) Why Belden Superior shielding Lowest capacitance

13 © 2013 Belden Inc. | 13 © 2012 Belden Inc. | | Page 13 Application Issues Reflected Wave Voltage Effects Motor failure and downtime Cable failure (wet THHN) Mitigation Lowest Capacitance cable Output reactor (an immediate 3-8% efficiency loss) Definition A voltage spike originating at the motor, caused by the impedance miss match between the motor and cable Why Belden Our 600V cables have a minimum 5500V Corona inception voltage (CIV) wet THHN can be 1600V or less Lowest capacitance increases distance before harmful voltages are created by up to 3x compared to THHN

14 © 2013 Belden Inc. | 14 Reflected Wave Voltage Application Issues

15 © 2013 Belden Inc. | 15 © 2012 Belden Inc. | | Page 15 Application Issues Installation reliability and safety Issues Cable/motor failure and degradation with PVC/Nylon Reference manufacturers cable selection instructions System noise issues Downtime Liability

16 © 2013 Belden Inc. | 16 © 2012 Belden Inc. | | Page 16 The 2kv Myth Issues In the 90s VFDs lead to high failure rate on 600V THHN installations The engineering community began to specify 2000V THHN as a result 600V VFD cable, even the weaker construction grade, has higher dielectric strength than 2Kv THHN Belden has never had a claim for dielectric failure in 16 years making 600V VFD Cable Code requirements are satisfied by 600V cable

17 © 2013 Belden Inc. | 17 © 2012 Belden Inc. | | Page 17 Belden Features Benefits 50% more copper than most 3C symmetric -300% better common mode current protection Enhanced flexibility Feature Foil Braid – Drain and full sized ground

18 © 2013 Belden Inc. | 18 © 2012 Belden Inc. | | Page 18 Belden Features Benefits 4-8 times higher surface are means reduced High Frequency Losses Cooler operation Enhanced flexibility Flexible motor supply rating Feature Flexible Stranding

19 © 2013 Belden Inc. | 19 © 2012 Belden Inc. | | Page 19 Belden Features Benefits Reduced cable charging current Longer critical distances for reflected wave buildup Longer cable life Feature Oversized wall thickness for lower capacitance (0.045 vs 0.030)

20 © 2013 Belden Inc. | 20 © 2012 Belden Inc. | | Page 20 Belden Features Benefits Better HF shielding than a single 5mil Reduced noise Enhanced flexibility Feature Dual copper tapes

21 © 2013 Belden Inc. | 21 © 2012 Belden Inc. | | Page 21 Belden Features Benefits Corrosion resistance Thermal stability Connection reliability Feature Tinned stranding

22 © 2013 Belden Inc. | 22 © 2012 Belden Inc. | | Page 22 Belden Features Benefits Reduced installation costs Enhanced mechanical performance Feature ER rating

23 © 2013 Belden Inc. | 23 Belden Confidential Input Line Reactor Output Line Reactor Common Mode Choke Motor terminator/snubber VFD Cable A Comparison of Mitigation Strategies

24 © 2013 Belden Inc. | 24 © 2012 Belden Inc. | | Page 24 Input Line Reactor Benefits Protect the drive from line transient damage Reduces Overvoltage faults Reduces Harmonic currents Feature Adds impedance on the Line side of the drive

25 © 2013 Belden Inc. | 25 © 2012 Belden Inc. | | Page 25 Output Line Reactor Effects Can be protective of non inverter motors Reduces Dv/Dt rise time downstream of the reactor thus increases critical distance Can have harmonic interaction with Motor Has high associated efficiency losses (3-8%) Reduces motor voltage and torque Feature Adds impedance on the load side of the drive

26 © 2013 Belden Inc. | 26 © 2012 Belden Inc. | | Page 26 Common Mode Choke Effects Reduction of common mode current Reduces noise emissions Does no reduce EMI or RFI at all Feature Reduces common mode current

27 © 2013 Belden Inc. | 27 © 2012 Belden Inc. | | Page 27 Motor Terminator/Snubber Effects Reduction of reflected wave voltage Protection of motor and cable systems Great for vulnerable motors on very long leads Feature Burns of reflected wave energy as heat at the motor

28 © 2013 Belden Inc. | 28 Belden Confidential Best: - Fine strand, tinned copper - XLPE Insulation - 3 power conductors and 1 full size ground - Foil and braid shields - Manufacturers are in the on machine world Pete Comber Competitive landscape There is no standard for VFD cables, but we can categorize the product available: Better: - Stranded copper (some have tinned) - XLP or THHN insulation - 3 power conductors and 3 reduced size grounds - Copper tape shield - Manufacturers are in the power cable market Good: - Bare copper (think tray cable stranding) - THHN insulation - 3 power conductors and 3 reduced size grounds - Copper tape shied - Manufacturers are from any background

29 © 2013 Belden Inc. | 29 Belden Confidential Upgraded THHN Construction Grade VFD XHHW 4C vs 3C Symmetric designs optimized for high frequency Placeholder for Pete Comber Competitive landscape There is no standard for VFD cables

30 © 2013 Belden Inc. | 30 Belden Confidential No Common Mode Current Containment or Shielding Do you want to put the noisiest signals in the plant in unshielded cable? Cost does not include conduit and labor, with ER or Tray, these costs are dramatically reduced Faster Ring Up of Reflected Wave Voltages Higher cable charging current – Significant for small drives Short cable life on long runs - 10yr MTBF estimates-Not rated for 1600V No protection from capacitive coupling - Shielding Conduit transitions have high HF impedance-Reduced surface area Faults in THHN may not be catastrophic but periodic due to pin holes Compared to THHN in Conduit

31 © 2013 Belden Inc. | 31 Belden Confidential When we are comparing to Service Wire/General etc. And there is no spec or performance standard IF No Flexible Motor supply rating is required and flexibility is not desired The environment is not noise sensitive Cable Charging, and EMI, and RFI are the only issues When to use Belden C Series (Construction Grade) There is no standard for VFD cables

32 © 2013 Belden Inc. | 32 Belden Confidential Directly connect the Shield at the Motor and Drive Only Do not introduce jumping off points for CMC through shield termination- Use Insulated glands Do not cut the shield between the motor and drive Do not use intermediate termination for the conductors if safely avoidable Maintain maximum spacing from sensitive circuits and route cables away from instrumentation and networks Reference the Belden VFD Termination guide Advice for Proper Instalation The following are best practices for VFD Cable installation and Termination:

33 © 2013 Belden Inc. | 33 Belden Confidential Run a separate ground to the safety disconnect Avoid contact between the VFD cable grounds and shield with the ground in the disconnect If you must cut the grounds, terminate through an isolating terminal block or connection Advice for Proper Instalation Using VFD Cables with Safety Disconnects

34 © 2013 Belden Inc. | 34 Belden Confidential Run the Videos Termination videos

35 © 2013 Belden Inc. | 35 Belden Confidential You may have issues you dont know Process measurement error Overcurrent or ground fault trips Loss of efficiency Network errors Remember that ground plane pollution is additive, one bad install may not cause a problem, but the accumulation of many bad installs may cause problems in the future Scenario Based Q&A A customer resiest VFD Cable because he always uses THHN without issue

36 © 2013 Belden Inc. | 36 Belden Confidential What Questions should you ask How long are the motor leads Is the motor wet What type of failures How large is the motor What are the likely causes of failure Reflected wave voltage Bearing Currents Scenario Based Q&A A customer has contacted you because he experiences frequent motor failures on pumps driven by VFDs

37 © 2013 Belden Inc. | 37 Belden Confidential How is the drive cable run How long are the motor leads What type of cable has been used? Does it correlate with drive starts stops enables Scenario Based Q&A A customer experiences network drops on the mixer ever since the line was upgraded Could it be drive related?

38 © 2013 Belden Inc. | 38 Belden Confidential What issue do you think is the likely cause How long are the motor leads What type of cable has been used? Scenario Based Q&A A contractor has installed a large drive system for airport baggage handling. On commissioning many of the drives trip on overcurrent or will not run

39 © 2013 Belden Inc. | 39 Paralleling and TC-ER Rating Installations savings Material –No metal conduit –No metal clad cable Labor –Less time Maintenance –Simplifies equipment moves, no conduit to re-route / install

40 © 2013 Belden Inc. | 40 Belden Confidential Sizing Parallel VFD Cable: Parallel Conductors Amps1/02/03/04/ Single Parallel Triplex Quad Per NEC (16) When installed in Cable tray with air spacing, or in separate conduits When parallel in Single conduit additional derate is required

41 © 2013 Belden Inc. | 41 Belden VFD Resources & Tools Industrial Cable VFD Page on Belden Website Industrial Cable VFD Page on Belden Website Unarmored VFD cable Termination Guide Unarmored VFD cable Termination Guide VFD Cable solutions guide Belden VFD Product Bulletin Belden VFD Cable Selection guide (based on Motor HP) Belden VFD Cable Selection guide (based on Motor HP) Choosing the Right Cable for your Variable Frequency Drive (VFD) System White Paper Choosing the Right Cable for your Variable Frequency Drive (VFD) System White Paper Building a Reliable VFD System White Paper Building a Reliable VFD System White Paper Control Engineering Belden1 41

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