Overview of variable frequency drives for material handling, pump control and pumpjacks.

1. Introduction to Variable Frequency
Drives and Rod Pump Control
Freddy Jones, Manager – Offer Development

2. Variable Frequency Drives Overview

3. Variable Frequency Drives Overview
By 2050, demand for energy will have doubled, but CO2 emissions must be
cut in half!

4. Variable Frequency Drives Overview
Industrial Chiller Unit
Cooling Tower Fans
Industrial Pumps

5. Variable Frequency Drives Overview
…with another 15% devoted to material handling applications
Baggage Handlers
Cranes/Hoists
Conveyors

6. Variable Frequency Drives Overview
•The vast majority of these instances offer very little control other than:
–Turn it on
–Run it at full speed
–Turn it off
Square D Motor Starter

7. Variable Frequency Drives Overview
•Running motors this way is very inefficient and contributes to increased
wear and tear on both the motors and the components that they power
– Starting and stopping motors by using across-the-line contactors can cause
undesirable consequences
• Inrush current of 8X normal
• Overheating
• Undue stress on shafts, pulleys, belts
• Harmonics created by numerous
simultaneously starting motors
• Interference transmitted back through system
High Inrush Current at Motor Startup
– The output required of a system can change over a period of time
•HVAC systems don’t need to run at full speed both day and night
•Pump flow rates need to change at various times throughout the process

8. Variable Frequency Drives Overview
•Starting, stopping and throttling motors requires human intervention
–Timers can be installed, but they don’t solve the starting problem, and they
still only provide on/off control
–Soft or reduced-voltage starters can be used, but they can only ramp up to
(or slow down from) full speed
–Flow control is traditionally done by restricting the medium in some way
using valves or dampers

9. Variable Frequency Drives Overview
•Many material handling applications require controlled starting and
stopping either when automated or under human control
–Overhead crane applications where swinging and swaying effects need to
be dampened
–Conveyors and moving equipment where products might be sensitive to
breakage due to backlash during acceleration and deceleration

10. Variable Frequency Drives Overview
•The Variable Frequency Drive (or VFD) offers ways to manage these
issues
–Schneider Electric offers a complete range of Altivar® VFDs for any
application

11. Load
Better power factor,
reduced harmonic
distortion, lower
sensitivity to incoming
phase sequencing
Variable Frequency Drives Overview
Incoming three
phase power
Using Variable Frequency Drives
•When connected to an AC motor, the drive delivers controlled power to
the motor at constant V/Hz ratio…
Pulse Modulated
Output
Rectifier converts
incoming power to
DC, then inverter
converts back to
controlled pulse AC

12. Variable Frequency Drives Overview
Using Variable Frequency Drives
•The primary benefit of using VFDs is energy efficiency
–Power consumption by a VFD as a function of speed is considerably lower
than a motor alone, especially when run at less than full speed
% Power
Consumed
% Flow
Example: Desired flow
rate is 80%
Using VFD to slow
motor (rather than
running motor at full
speed and using
valves) saves up to
50% of power
consumed
Simple Pump Application
Flow control with VFD vs. valves or dampers

13. Variable Frequency Drives Overview
Click “Energy Savings Calculator” below for web-based demo…

14. Variable Frequency Drives Overview
Two primary types of VFDs
•Variable Torque
–Found in applications where torque increases as
a function of speed
–Primarily centrifugal pumps and fans
–The faster you run these applications, the torque
(and hence the power) required to do so increases
exponentially
•Constant Torque
–Torque only changes directly proportional to
speed
–Constant torque applications include mixers,
compressors, conveyors

15. Variable Frequency Drives Overview
Using Variable Frequency Drives
•The VFD is programmable for managing the entire
process
– Can be programmed to ramp up slowly and smoothly at start
up, thus reducing high starting torque and current surges
– VFDs can maintain motor speed at values less than full
speed, enabling considerable energy savings over motors
alone
– VFDs can speed up, slow down, stop, restart, and vary
torque over the course of time, allowing for complete
automation of the process over a day, a week, or more
– VFDs offer the added feature of acting as phase converters,
converting single phase input power into three phase output, a
situation often encountered in remote locations such as field
irrigation or pumpjack sites

16. LOAD
Variable Frequency Drives Overview
Three phase
power in
Using a PLC to control drive
Feedback
from load
source
PLC issues commands
to the drive
Drive
controls the
load

17. LOAD
Variable Frequency Drives Overview
Three phase
power in
The ATV 61 & 71 with Integrated Machine Controller
(IMC) Card
Feedback from
load source
Drive
controls the
load
Integrated controller
card mounts right
into the drive
External PLC is
eliminated

18. Refresher: “Pumpjack: 101”

19. Pump Jack Operation:
“Artificial lift” system
extracts oil from a reservoir
using a reciprocating rod
with a valve mechanism at
the bottom
Rod Pump (Pump Jack) Refresher
Oil Production Issues:
1. Maximizing productivity
2. Maintenance and downtime
costs caused by equipment
wear
3. Access to remote equipment
4. Reducing energy costs

20. Beam
Bridle
Stuffing Box
Crank Arm and
Counter Weights
Polished Rod
Basic Pump Jack Components
Drive Enclosure
Pump
(underground)
“Horse” or “Donkey”
head
Motor –
traditionally
NEMA D, but often
NEMA B when
used with VSD
Gearbox
Belt Guard

21. Ground/surfaceGround/surface
Fluid/Oil
Perforations
Standing valve shut
Downstroke
Traveling valve open
Downward
motion of
plunger causes
standing valve to
close and
traveling valve to
open – fluid
flows up through
plunger.
Tubing
Casing
Stuffing
Box
Upstroke
Standing valve open
…creating
negative pressure
in barrel, which
opens the
standing valve
and more fluid
flows in.
Traveling valve shut
With traveling
valve now shut,
plunger lifts
column of fluid
upward as it
rises…
Fluid exits stuffing
box by pipe
If pumping at correct
speed, fluid level is
maintained.
Anchors

22. Pump Jack Issues and Problems: Why Avoid
Over-pumping?
Fluid Pound
• Occurs when plunger hits the
fluid on the down stroke
• Worst case is when pump fill
<=50%
• Rod string compresses, twists,
and may eventually break
• Plunger “hammers” the fluid
• Production loss
Ground/surface
Desired fluid
level
Plunger direction
Full weight of
fluid column is
still in plunger
as it begins
downstroke.
Fluid does not
fill barrel
completely,
leaving a gap.

23. Pump Jack Issues and Problems: Why Avoid
Over-pumping?
Fluid Pound
• Occurs when plunger hits the
fluid on the down stroke
• Worst case is when pump fill
<=50%
• Rod string compresses, twists,
and may eventually break
• Plunger “hammers” the fluid
• Production loss
Ground/surface
Desired fluid
level
Plunger direction
Lack of fluid in
barrel means
traveling valve
doesn’t open
until it hits the
fluid, creating a
pounding effect.

24. Gas Compression (Gas Lock)
• Results from very low pump fill
• On the down stroke, the standing valve
is closed; the travelling valve also
remains closed. The gas is
compressed
• On the up stroke, the gas expands but
both valves remain closed
• The plunger travels up and down
without pumping oil. This results in
energy waste, production loss, and
mechanical wear as the plunger is no
longer lubricated
Pump Jack Issues and Problems: Why Avoid
Over-pumping?
Ground/surface
Level is so low
that plunger
movement does
not draw fluid
through the
standing valve.
Plunger direction
Desired fluid
level

25. Gas Compression (Gas Lock)
• Results from very low pump fill
• On the down stroke, the standing valve
is closed; the travelling valve also
remains closed - the gas is
compressed
• On the up stroke, the gas expands but
both valves remain closed
• The plunger travels up and down
without pumping oil. This results in
energy waste, production loss, and
mechanical wear as the plunger is no
longer lubricated
Pump Jack Issues and Problems: Why Avoid
Over-pumping?
Ground/surface
Plunger direction
Neither valve
opens as the
plunger travels
up & down,
allowing a gas
pocket to form in
the barrel.
Desired fluid
level
Result of equipment
damage…

26. Pump Jack Issues & Problems: Over-pumping
Consequences
Pulling the rod string is very
expensive - not only due to
labor and equipment, but lost
production costs can run into
tens of thousands of dollars
The damaged rod
string must be pulled
from the well for
repairs

27. Why is Pump-Off Control important?
●How does the pump operator get the most
production from his well without over-
pumping and risking equipment damage?
● Pump too little and you don’t get maximum
production
● Pump too much and you create a “pump-off”
condition (no fluid in the well barrel), harming
the equipment
●Rod Pumps have historically been run
with across the line contactors, the pump
regulated by periodically turning off the
motor
● Starting and stopping was initially done by
hand
● The use of timers meant this could be done
“automatically” without having to be present
at the well site
● How long to allow pump to sit idle before
restarting? Best guess? Trial and error?

28. Why is Pump-Off Control important?
●Using a VFD, with its ability to act as a
timer and a soft starter allows the pump
operator to accomplish the same thing, plus
some benefits:
● Less wear and tear on the motor than across
the line starters
● Ability to run at speeds less than maximum,
allowing for reduced energy consumption
● Smoother input current and ability to operate
using single-phase power.
●Significant problem still remains:
● Pumper still doesn’t know how long to
let pump sit idle between runs
● Limited ability to react to unexpected
changes in the well
● No further insight as to what is actually
happening deep down in the well

29. How to Address the Problem?
The Schneider Electric ATV71 drive with Integrated Machine Controller (IMC)
card acts as a drive and a PLC-in-one to control the well in real time based on
well conditions…

30. Fully Automated Pump-Off Control Options
●Basic: Torque-Only Control:
● Uses motor torque measured by the drive to
monitor the load on the rod string to control pump
operation
● Cost effective solution for wells of 1500m or less
● Think: “entry level” solution (there are a lot of
these in the market)
● Still not the most accurate picture of what’s
happening (uses no load cell)
●Advanced: Dynamometer Card Control:
● Load cell measures forces acting on the rod
string; controller uses this data to manage pump
operation
● Creates an x-y plot, providing ultimate
optimization using well data and visual system
tuning
● Downhole control uses an advanced algorithm to
determine rod load at the bottom of the well

31. So, just what is a dynamometer card?

32. Bottom of Stroke
Load Cell collects
data as rod string
moves up and
down…
Understanding the Dynamometer Card
Displacement (up and down)
Load
…and the data is
plotted onto the graph
Ground/Surface
Stuffing Box

33. Dynamometer Displays: Using Load Cell and
Pump Position Data
Plot of load vs. position at the load
cell for one complete cycle (up-and-
down stroke) actually looks like this -
called a “surface” card
Displacement
Load
The same data, after correcting
for rod stretching, flexing, and
stress wave propagation, looks
like this, giving a clear view of
what’s happening at the bottom
of the well (“downhole” card)
Displacement
Load

34. Displacement
Load
A
Diagnostics with Downhole Dynamometer Card
Bottom of Stroke: Beam is at lowest
point; load and displacement are at
point “A”
A Bottom of Stroke
Load Cell
Minimum
Load
Minimum
Displacement

35. Displacement
Load
A
Bottom of Stroke: The instant torque
is applied to the beam, the traveling
valve shuts and load increases to point
“B”
B
A, B Bottom of Stroke
Diagnostics with Downhole Dynamometer Card
“Load” consists of the weight of the
fluid + the weight of the rod string as
measured by the load cell
Maximum
Load
Minimum
Displacement

36. Displacement
Load
A
Top of Stroke: As the beam moves
upward, load remains constant as
displacement increases to point “C”
B
Bottom of Stroke
C
A, B
C
Top of Stroke
Diagnostics with Downhole Dynamometer Card
UpstrokeMaximum
Load
Maximum
Displacement

37. Displacement
Load
A
Top of Stroke: Torque is reversed and
load drops back to point “D”
B C
A, B
C, D
D
Top of Stroke
Bottom of Stroke
Diagnostics with Downhole Dynamometer Card
Fluid is released (traveling valve is
open), so plunger can move freely
back down the barrel
Maximum
Displacement
Minimum
Load

38. Bottom of Stroke: Load and
displacement return to point “A”
Bottom of Stroke
Displacement
Load
A
B C
D
Top of Stroke
Diagnostics with Downhole Dynamometer Card
A, B
C, D
DownstrokeMinimum
Load
Minimum
Displacement

39. Optimizing Well Performance
“Ideal” Downhole Dynamometer Card
•Indicates rod load at the BOTTOM of the well versus rotation at top
•The “ideal card” is a fully optimized system in terms of production and
equipment operation
A – C = Upstroke
C – A = Downstroke

40. Ground/surface
Plunger direction
Diagnostics with Downhole Dynamometer Card – Fluid
Pound
Load
Displacement
Traveling valve still closed
as downstroke begins
A
B C
D

41. Ground/surface
Plunger direction
Diagnostics with Downhole Dynamometer Card – Fluid
Pound
Load
Displacement
Sudden impact with fluid
rapidly opens valve
A
B C
D’
Wasted Motion/ No
Production
Plunger only fills
from D’ to A
D

42. Diagnostics with Downhole Dynamometer Card
●Provides significant information about the well and its performance
●Identifies issues limiting production and damaging equipment
●Our solution uses the dynamometer card from each pump stroke to
constantly optimize performance, even under changing conditions

43. Diagnostics with Downhole Dynamometer Card
A couple of examples…
Unanchored Tubing
Position
Force Pump and tubing moving together;
force can not reach maximum until
tubing movement/stretching stops.
Pump and tubing move together on
downstroke. A portion of potential
pump fill is lost.
Pump Tapping (top or bottom)
Force
Position
Plunger hits top of pump while on
upstroke; results in a spike in the
force reading
Plunger hitting bottom momentarily
causes a drop in force on the rod string

44. Diagnostics with Downhole Dynamometer Card
0Actual Oilfield Data, Perryton, TX

45. Diagnostics with Downhole Dynamometer Card – Effective
Stroke and the RPC
Load
Displacement
Total Stroke
Max
Load
Min
Load
Fill Status = Effective Stroke/Total Stroke
A
B
C
Downstroke
D
Effective Stroke
D’
In this situation, Fill is only
about 55%
From B to C, pump is lifting
From D to A, pump is refilling
Upstroke

46. Basic system response is largely governed by a calculated
value for Fill Status
•Fill Status = an estimate of % pump fillage for each stroke of the pumpjack as
calculated by the RPC algorithm
Fill Target vs. Fill Minimum
•Fill Status, relative to Fill Target -
determines whether the system increases
or decreases speed (RPC system
changes speed as often as the user-
determined “Speed Change Strokes”
setting allows)
•Fill Status, relative to Fill Minimum -
determines when the system enters
Pump Off status (RPC system enters
Pump Off when “Pump Off Count Limit” is
reached, and remains off for user-
determined period of time)
Diagnostics with Downhole Dynamometer Card –
Fill Status

47. Ground/surface
Tying it all together…
Keeping it in the “sweet spot”
•By monitoring the load on the rod
string, the Rod Pump Controller
continually adjusts the speed of the
pumpjack so the pump operates in its
“sweet spot” – the point where the
pump is lifting a full load of fluid with
each stroke, while not allowing the
fluid inside the casing to drop below
the desired level
•This is Rod Pump Optimization!
•The Downhole Solution provides
both Control and Diagnostics

48. The Schneider Electric RPC
Components and Installation

49. 3. Complete RPC Drive Cabinet
Schneider Electric Rod Pump Controller
1. Rod Pump Controller Kit - upgrade an existing ATV71 drive
Three Options for the Customer:
2. RPC Panel Builder Bundle – Includes kit and drive only

50. Schneider Electric Rod Pump Controller Kit
● Integrated Machine Controller
Card (IMC) for Altivar 71 Drive
● Rod Pump Control algorithm
loaded on IMC
● Proximity Sensor with required
cables and mounting hardware,
brackets & magnets
● Relays – (2) Run Interrupt and
optional Start Warning Indicator
● Load Cell with required cables and
hardware (Downhole only)
● Instructions for installation and
commissioning

51. Hardware supplied in the Schneider Electric
RPC Kit…
Proximity Sensor
mounted behind crank arm
Load Cell Sensor
installed on bridle
Run Interrupt Relay (RIR)
mounted on DIN rail in cabinet
Integrated Machine
Controller Card
Installed into drive

52. Schneider-built Enclosed Pumpjack Drive Cabinet
Enclosed drive comes with IMC card,
relays, and other internal components
already installed (load cell and prox
sensor must still be installed on site)
Door-on-door feature allows access to
drive controls without opening cabinet

53. *The cabinet should already be mounted in its
permanent position on site prior to arrival of the
start up technician. Schneider Electric can also
perform installation as a separately quoted job.
Schneider-approved technicians will mount the
necessary RPC components into the drive*

54. Hardware Start Up Steps
Simple Commissioning Steps
•Shut down all power to field drive
•Install IMC into drive and connect
to power supply (kits only)
•Install relays and connect to the
IMC (kits only)
•Mount load cell onto bridle
(performed by customer) and
connect cable to IMC
•Mount proximity sensor on
pumpjack and connect cable back
to IMC
•Power can now be restored to the
drive cabinet
•Ready to set up operating
parameters

55. Install the Load Cell
Important: Load cells must be installed with local
assistance. This will be coordinated with the customer prior
to set up day.

56. Connect the Load Cell Cable to the Load Cell
Load cell cable, once connected, must be routed back to the drive cabinet and
secured in such a manner so as to avoid entanglement or trip hazards
(configuration shown may vary; for example only)

57. Proximity Sensor Bracket & Hardware
Be careful
attaching magnets
to the bracket - the
high-strength
magnets create a
serious pinch
hazard!

58. •Note very tight clearance between
Proximity Sensor and crank arm,
ensuring the best possible signal
each time the arm passes the
sensor
•Secure the cable using UV-
resistant, outdoor-rated cable ties
(or similar), and carefully route the
cable back to the drive cabinet so as
to avoid tripping hazards
Install the Proximity Sensor

59. RPC HMI Software Interface

60. RPC Configuration: Interface with the RPC Drive
HMI Configuration Software for PC
•Minimum: 1 license required (typically 1 per PC used)
•1 license will support multiple wells

61. RPC Configuration: Install RPC HMI Software
Installation CD and USB license key are included
for software

62. Multiple Ways to Access the RPC

63. RPC Configuration: HMI Software, Hardware &
OS Minimum Requirements: direct connection*
Component Minimum (1-2 wells only)
Processor Dual Core (2x) 2GHz CPU
RAM 2 GB
Operating System Windows XP Professional (SP3) or
greater; or Windows Server 2003
(SP2) or greater.
Available Disk Space 500MB up to 100 GB (may require
separate disk for historic data)
Graphics Adapter High performance graphics card
Browser Internet Explorer 6 or above (cannot
use Firefox)
* Requirements will increase with number of wells to be accessed via the
same system – confirm configuration ahead of time

64. RPC Configuration: Install RPC HMI Software
Follow the instructions that appear upon loading the
Installation CD

65. Screen Shots/Features

66. Login/Landing Page
•Choose between multiple wells to view
•Create/delete additional wells
•Manage user access

67. Status Page
•Monitor well “vital signs”
•View Dynamometer Cards in real time

68. ATV Drive Configuration
•Set up ATV71 drive parameters without using the drive keypad
•Transfer all the settings to the drive with the click of a button

69. Well Fault Detection
•Pre-program how the RPC unit responds to problems/faults caused by
external factors…
•belt slippage, errant sensor readings, loss of signal, etc.

70. History Trends & Events
•Choose from a variety of parameters to track
•View real-time data or look back at stored trends

71. History Cards
•Look back at historic cards to diagnose well problems
•Cards are accessible in real time, or download the previous 18 stored cards

72. Pump Control Configuration
•Set up all pumping parameters such as max/min speed, pump-off settings,
start-up alarms
•Customize pump-off wait times or let the RPC determine them for you

73. Well Data Configuration
•Manage pump API data and calibrate strokes/minute vs. motor speed
•Add rod taper information and manage well parameters

74. Time & Network Configuration
•Manage network set up, counters and timers
•Save well parameter settings and upload them to other wells

75. Get More Information…

76. Approved RPC Channel Reps and Territories
Company Territory
Latech
Daco
Pantech
RDS
DMC-Carter Chambers
Westerman
Beabout Company
Industrial Automation Group
Utah, Western Wyoming, Idaho, Montana
Oklahoma, No. Arkansas, Kansas
West & Central Texas, Southern New Mexico
South Texas
Louisiana, East Texas
Western Pennsylvania, Ohio
Northern California (Bakersfield)
Northern New Mexico, Colorado, Eastern Wyoming,
North & South Dakota, Montana
Berg Johnson Minnesota

77. Contact Schneider Electric to Inquire…
• See your local Schneider Electric Sales Person
• Call us directly at: 919-217-6491
• See the web site and download a brochure at:
•http://www.schneider-electric.us/sites/us/en/solutions/industrial-
solutions/oil-gas/oil-and-gas-rod-pump.page