EZ-FLO Weighing

  • Products & Services
    • Impact Flow Meter Product Line
      • Small Mouth Impact Flow Meters
        • Impact Flow Meter Customers
      • Feeder Scales
      • Low Profile Impact Flow Meters
      • Pneumatic Conveying
      • Weigh Loss Controller
      • Belt Scales
    • Applications
      • Asphalt Mix Plants
      • Baghouse Dust
      • Cement (CTB) & Grout Plants
      • Frac Sand & Mining
      • Dry Foods & Grains
      • Mineral Filler
      • Liquid Level
      • Pellets & Plastics
      • Recycling
      • Tests
    • Silos, Feeders & Pugmills – New or Used – Sale or Rent
      • 200 Bbl Surge Bin
      • 350 Bbl Mineral Filler Silo
      • 450 Bbl Mineral Filler Silo
      • Fiber Feeders
      • Pugmills
    • Controls and Engineering
      • Accuracy Monitor
      • Tank Gauges – Vertical or Horizontal
      • Batching Controls
      • Blending Controls
      • Weigh Loss Controller
  • Training
    • Plant Operation Training
      • Plant Production Attachments
    • Electro-Mechanical Systems
      • Electro-Mechanical Attachments
    • Safety
      • Safety Attachments
    • Process Quality Control
      • Process Quality Control Attachments
  • Articles
    • Asphalt Pro Articles
      • RAS Solids Impact Flow Meter
      • Impact Flow Meter Controls the Uncontrollable
      • 2021 and Beyond Clarence Richard Company – The New Zoom Plant Schools by Steve Klein
      • How to Control Dust During Production
    • NISA (National Industrial Scale Association)
    • Powder & Bulk
      • Instrumentation: Trust but Verify
      • Dry Flow Meter Continuous Weighing: The Big Picture
    • Asphalt Contractor
    • Asphalt News Rag
      • Solids Impact Flow Meter Batches and Blending Combination Application
      • Dry Impact Flow Meter System Delivers
      • Impact Flow Meter Replaces Belt Scale
      • EZ Flo Continuous, Weigh Loss, Scale Controller with Low Bin Level Alarm, Bin Bridging Alarm and Bin Air Blast Control
    • Patents
  • Support
    • About Us
    • Contact Us
    • FAQ’s
    • Glossary
    • Owners Manuals
      • EZ Flo Scale – Impact Flow Meter
      • Low Profile Impact Flow Meter
      • Weigh Loss Scale Controller – Owners Manual
      • Horizontal Tank Gauge
      • Vertical Tank Gauge Instructions

You are here: Home / Control Systems / Variable Frequency Drives

Variable Frequency Drives

December 1, 2016 By Clarence Richard

We shall start our blog discussing potential energy savings devices such as VFD drive plant retrofits. Right now, your entire industry is not taking advantage of the benefits and, in some instances, are installing an incomplete system. Come learn and come share.

Variable Frequency Drives have been around for a long time varying the speed of motors. VFDs can save you energy in some instances.

I want to focus on the quick paybacks that are available at the asphalt mix plant in those some instances.

If any of your plants are  running at half the speed most the time and you run about a 1,000 hours a year, you want to read further. At the moment, we are adding three 200 hp vfds and inverter duty motors to replace the two motors at the exhaust fan and the burner fan motor. These loads are centrifugal loads lend themselves to solve a problem the utility companies would like fixed. Most utility companies will chip in a healthy rebate. The utility company is chipping in $60,000 to this project. The customer chips in the balance and finds his Payback is about a year.

The savings projection the utility company is projecting was compared to our calculations and those of other engineers in like applications.

The variable speed fans replace the variable flow dampers and the actuators. The fans begin freewheeling as the damper is being modulated so less air is being pulled through. This lighter load makes the utility company to use more power than normal to get the work done. Consequently, the user gets charged for this.

The VFDs work well with the utility companies and the rest of the equipment on the power grid when properly filtered with reactors.

When you have an application like this, get your utility company and a consulting-contracting company that can work with your utility company to install what is beneficial to both the utility and the customer.

Since you are changing air flows in the combustion process, a consulting-contracting company that can design the electrical retrofit to your application and adjust the air to fuel ratio with a combustion analyzer is important.

So, it was a good idea on commercial power. How good of an idea are VFDs on portable generators? It appears to us, you are probably better off staying with damper control. Contacting your generator service department is a good start when you must add VFDs. They will probably suggest adding a Harmonic Inhibitor besides line and load filter reactors. Now you are loading up a portable plant with a bunch more heavy and big components.  I am not sure you want to go here.

Some people are adding VFDs to adjust the speed of their drum. In most instances, users are just varying the speed 5% to 10% to get the greatest heat recovery from the exhaust gases. This speed reduction is not much, normally does not require changing the motor to an inverter duty motor. The motor shaft does require grounding. A split ring, brush grounding kit must be added to each motor.

Clarence Richard

Filed Under: Control Systems, Retrofitting

Copyright © 2005–2023 Clarence Richard Co. • EZ-FLO Weighing · Sitemap