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  • Users: cfordyce
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  1. cfordyce

    encoder feedback on PowerFlex70 drive?

    I have a standard 5hp 3ph induction motor running a pump through a gear reducer. Inverter controlled (Allen-Bradley PF70 drive). I have very poor speed accuracy (4% error) using open loop mode. I want to install an encoder on the motor and run in closed loop control. I am wondering what ppr...
  2. cfordyce

    BUDGET ESTIMATES FOR BUILDING UTILITIES

    Hello. I was wondering if there are posted or recommended budget numbers for utilities costs for a large facility (manufacturing). If they exist, I assume they would be dependant on the seasonal weather conditions experienced in that area. (I'm in Ontario - about 50%-50% summer-winter balance)...
  3. cfordyce

    Energy savings with Inverter drive

    Hello, I need an approx calculation of energy savings for a fan application. Currently the 44hp motor is run at line voltage and a damper is adjusted to get approx half the rated air flow from the fan (1/2 load). We want to install an frequency inverter to adjust the fan speed to deliver the...
  4. cfordyce

    replacing DC motor with AC motor

    I have heard that it is recommended to upsize the hp when replacing a DC drive with a 3 phase AC drive. Is this still a recommended practice? I have a 240VDC 10hp 1750rpm drive to be replaced with a 575VAC 3ph drive w/inverter. Should I select a 12.5 or 15hp inverter and drive? Thanks. CAF
  5. cfordyce

    Electrical Code

    I am installing 100hp air compressors. I am wondering if I put the breaker panel within line of site from the compressors, can I eliminate the local fused disconnect at each compressor? The breaker would be the point of lock-out. Thanks. CAF
  6. cfordyce

    Induction Heaters

    Looking for a company with expertise in custom induction heater applications. We have some induction heaters on a vessel that was built back in '67. two of the four heater coils have failed recently. We need a repair/replacement.
  7. cfordyce

    European Voltage Equipment used in North America

    I have 400V (380V) rated production equipment in my Plant which is comming from Germany. Up til now we have special ordered step-down powee transformers to supply this equipment with it's rated 400V 3ph power. I noticed that the spec on the equipment indicated an 'PERMITTED RANGE OF VOLTAGE...
  8. cfordyce

    Use of Manual Motor Protector

    Can a Moeller PKZMO Manual Motor Protector be used for general(other than motor load) cct protection in lue of fusing/cct breaker? According to Electrical Code (Canadian or American)? CAF
  9. cfordyce

    Quick Electrical Code Question...

    I have a 600V bus with a 200A rated plug on it. The 200A plug is fused at 150 A. We have changed the single wire lug connections on the plug to double wire connections to feed two machines from one bus plug. At the machine control cabinet it is fused at 60A (some have a 75A breaker instead)...
  10. cfordyce

    Inverter Features to protect pump ...similar to shear pins???

    We have an Inverter driven motor driving a pump through a 40:1 gear reducer box. We keep breaking shear pins in the coupling between the gearbox and pump. Is there a fearture in a typical invert which would protect the equipment in a similar fashion as the shear pins? (Inverter is Allen...
  11. cfordyce

    Sizing a Transformer...

    I need to size a TX for a piece of equipment. 1)The manufacturers spec indicates a MAX KVA of 207KVA for the machine. 2)I add up all the motors on the machine and I calc a full load KVA draw of; 152 1KW motors 2 1.4KW Air conditioners 1 5.0KW motor 1 5.5KW motor plus some controls...
  12. cfordyce

    Bus Plug Fusing...

    Currently I have a 600V Westinghouse Bus Duct in a particular area of the plant. One 200A rated, 150A fused bus plug feeds two identical pieces of equipment. The majority of the equipment load is a 40hp motor in each machine. The protection at the machine is either a 60A time delay fuse or a...
  13. cfordyce

    Confusing nameplate data

    I have 10 machines, each with a specified maximum machine load of 168kVA. Each has 126 1kW motors, 2 5kW motors and some Inverters, controls, electronics, etc. The machines run at 380VAC. They are powered by a 600V bus through a 1000KVA 600:400 stepdown Transformer. I have an old record of...
  14. cfordyce

    Thermocouple Inputs

    I am replacing an old TI PLC and T/C input modules with Automation Direct's DL405 and Terminator I/O modules. The existing system utilizes 'ISOTHERMAL BLOCKS' between the T/C junction and the Input to the card. Is this required with my new PLC as well? Or does the Cold Junction compensation...
  15. cfordyce

    4-20mA Power source Question...

    Which is better loop power source for 4-20mA singnals - 24VAC or 24VDC? Why?
  16. cfordyce

    Signals: 4-20mA or 0-10VDC ???

    Which signal type is better? What are the best qualities of each? Is one better in a noisy environment? Does one have a lower failure rate? Which is more utilized today??? Anyones opinions would be helpful. Thanks.
  17. cfordyce

    Employee questioning health risks from 600VAC cables...

    An employee has a concern for his safety that I must address ASAP. He is worried about ‘carcinogenic’ EMR (electromagnetic radiation)from some Feeder cables in a close proximity to his office in our plant. His concerns are strengthened by the fact that the previous person to have that office...
  18. cfordyce

    Certified Electrician or not???...

    I have nowhere else to ask this so please clear this up. Is it against the law for anyone other than a certified Electrician (Journyman) to work within an Electrical Maintenance capacity in a Plant? What law? Please give me a reference to an Ontario Act. ,Law or Regulation. I believe it is...
  19. cfordyce

    RTD input to PLC...

    If a PLC does not have a special RTD input module, what is the best way to be able to read a RTD input with the PLC? Can an analog voltage or current input card be used with accuracy? Or are there economically feasable devices to convert the signal from the RTD? Any suggestions? The RTDs are...
  20. cfordyce

    Motor Breaker Sizing...

    Quick question. Can I put a 40A Breaker on a 20HP rated Inverter driving a 20HP fan motor??? The Inverter is an Allen Bradely 1336 Plus 2 model. Also, is RWU90 #10 wire OK?

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