Fairway Farms Swim Club

Pool Main Pump Motor: Difference between revisions

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Pool Main Pump Motor (view source)

Revision as of 11:34, 20 March 2022

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=== Starting and Stopping ===
=== Starting and Stopping ===


This is performed via the motor starter. Further details on hold, pending replacement with a VFD.
Prior to the spring of 2022, this was performed via pushbuttons on the motor starter.
 
Further details will be posted once the VFD is brought up.


=== Flow Adjustment ===
=== Flow Adjustment ===


The pump flow is adjusted via the butterfly valve on the output side of the pump.  The flow rate must be periodically adjusted via this valve as debris in the strainer basket and sand filters provides additional resistance.
Prior to the spring of 2022, pump flow was manually adjusted via the butterfly valve on the output side of the pump.  


In the future, a VFD may be used to reduce the motor speed, eliminating the need for manual adjustment via a valve.
Flow adjustment will be automatic with the VFD (details to follow).


== Maintenance ==
== Maintenance ==
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== Variable Frequency Drive ==
== Variable Frequency Drive ==


<b>IMPORTANT:</b> At this time, this section is for investigation purposes only.  It has not been determined when/if a VFD will be implemented.
=== Background ===


=== Justification ===
Prior to the spring of 2022, the main pump motor was controlled by a Square D 8536 latching motor starter (relay).  Start and stop operations were manually performed by pushbuttons.  Adjustment of the flow rate was only possible by positioning the butterfly valve on the output side of the pump.
 
As of Fall 2021, the pump is controlled by a Square D 8536 latching motor starter (relay).  The pump is manually operated via start and stop pushbuttons.  The flow rate is adjusted via the butterfly valve on the output side of the pump.
 
Removal of the motor starter and replacement with a VFD has been proposed.  This system would be implemented prior to the 2022 swim season.


Benefits to changing to the VFD include:
Benefits to changing to the VFD include:


* Motor speed can be automatically adjusted (via the [[Pool Systems Automation|automation system]]) to compensate for changes in flow rate due to the state of the strainer basket and sand filters.  A constant and flow rate can be assured until the strainer basket or filters become too clogged.  The automation system is NOT required to operate the drive.  In the event that the automation system is not operational (or remote VFD control is disabled), the VFD can be operated with start and stop pushbuttons in a manner very similar to that of the motor starter.
* The main pump motor speed can be automatically adjusted (via the [[Pool Systems Automation|automation system]]) to compensate for changes in flow rate due to the state of the strainer basket and [[Pool Filter Tanks|sand filters]].  A constant flow rate can be assured until the strainer basket or filters become too clogged.  The automation system is NOT required to operate the drive.  In the event that the automation system is not operational (or remote VFD control is disabled), the VFD can be operated with start and stop pushbuttons in a manner very similar to that of the motor starter.
* No need for the operator (managers or B&G personnel) to regularly adjust the flow rate due to changing conditions.  An improper flow rate:
* No need for the operator (the pool manager or B&G personnel) to regularly adjust the flow rate due to changing conditions.  An improper flow rate:
** Violates best practices and/or health department requirements if too low (minimum number of complete water turn-over cycles per 24 hour period).
** Violates best practices and/or health department requirements if it is too low (there is a required minimum number of complete water turn-over cycles per 24 hour period).
** Causes channeling in the sand filters due if too high.  This can lead to incomplete filtration (cloudy water) and requires opening and manually stirring tank sand to resolve.
** Causes channeling in the sand filters due if it is too high.  This can lead to incomplete filtration (cloudy water) and requires opening and manually stirring tank sand to resolve.
* Utility incentives will pay for a significant portion of the material cost.  As of 2022, DTE will reimburse up to $900 for a 15 HP VFD.
* Utility incentives will pay for a significant portion of the material cost.  At the time of the project, DTE reimbursed up to $900 for a 15 HP VFD.
* Enhanced safety with the addition of two emergency stop buttons, including one at the gallery level (near the pump).
* Enhanced safety with the addition of two emergency stop buttons, including one at the gallery level (near the pump).
* Reduced stress on the mechanical system during startup as the motor speed can be ramped up rather than instant-on.  This prevents "hammering" that can occur from an abrupt start.
* Reduced stress on the mechanical system during startup as the motor speed can be ramped up rather than instant-on.  This prevents "hammering" that can occur from an abrupt start.
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There are some downsides, too:
There are some downsides, too:


* Material cost (see the [[#Bill of Materials|bill of materials]]).
* The material cost (see the [[#Bill of Materials|bill of materials]]).  This is managed by creative purchasing - utilizing refurbished and surplus materials where possible.
* Added complexity.
* Some added complexity.
* Added failure points - including the addition of sensitive electronics in a harsh environment.
* Added failure points - including the addition of sensitive electronics in a harsh environment (corrosive vapors and dust).


An improvement in energy efficiency may be possible.  However, it is not confirmed.  Restricting the output flow on a centrifugal pump reduces the amount of work (pushing a lower volume weight of water).  Data in the appendix below confirms this to a point.
An improvement in energy efficiency may be possible.  However, it is not confirmed.  Restricting the output flow on a centrifugal pump reduces the amount of work (pushing a lower volume weight of water).  Data in the appendix below confirms this to a point.
=== Requirements ===
* Must withstand an ambient operating range in the 40 &deg;C to 50 &deg;C (122 &deg;F) range.  For the GS23-2015 at 75% load, 50 &deg;C, no de-rating is necessary up to a 4 kHz carrier frequency (SVPWM mode).
* Must be compatible with 240 VAC high-leg delta.
* A two-channel safety relay will be used.


=== Theory of Operation ===
=== Theory of Operation ===


The sections below are theoretical at this point, describing possible operation for the VFD controls.
NOTE: The sections that follow are still under development.


==== Reset ====
==== Reset ====
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=== VFD Unit ===
=== VFD Unit ===


==== Overview ====
This section has been updated to alter its context from research to implementation.  A majority of the data for "other" VFD units has been removed.
 
Cost is a major driver in the VFD selection process.  As noted, up to $900 will be reimbursed by DTE.  Longevity is an issue, too, as failure becomes a MAJOR issue for pool operation.
 
The consensus amongst "experts" (i.e. individuals with opinions in forums) is that:
 
* ABB or Allen Bradley drives are top-of-the-line, but come at a cost.  ABB drives are very easy to program (but expensive!).
* Automation Direct drives are inexpensive - but support is lacking.  Later-generation drives (such as the GS23, made by Delta) seem to receive positive feedback.  Earlier generations (GS1, GS2) are to be avoided.  Much of the negative feedback seems to be 10+ years old.
* Delta is usually regarded as "decent" (again, Automation Direct GS23 line).
* Teco may be a step up from Automation Direct and Delta?
* Vacon is well-regarded.
* Yaskawa is recommended both in online forums, and by engineers at a local industrial controls firm.
 
==== Yaskawa GA50U2042ABA ====


The present front-runner.
Yaskawa GA50U2042ABA:


* Priced at $842 via local distribution.
* The 2042 model sized for "normal duty" (ND) 15 HP which is appropriate for variable torque (VT) applications (i.e. centrifugal pumps).
* The 2042 model sized for "normal duty" (ND) 15 HP which is appropriate for variable torque (VT) applications (i.e. centrifugal pumps).
* Internal PCBs are conformally coated (IEC 60721-3-3, Class 3C2 for chemical gasses).  <b>This is a huge plus!</b>
* Internal PCBs are conformally coated (IEC 60721-3-3, Class 3C2 for chemical gasses).  <b>This is a huge plus!</b>
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* 391 W total loss @ 2 kHz, 42 A output.
* 391 W total loss @ 2 kHz, 42 A output.


==== Automation Direct GS23-2015 ====
{| class="wikitable"
!colspan="2"|Drive Catalog Code
!Description
!Comment
|-
!Product Series
|GA50
|
|
|-
!Region Code
|U
|Americas
|
|-
!Input Power Supply Voltage
|2
|Three-Phase AC 200 V Class
|
|-
!Rated Output Current
|42
|42 A
|
|-
!EMC Noise Filter
|A
|No Internal EMC Filter
|
|-
!Enclosure Protection Design
|B
|IP20/UL Open Type
|
|-
!Environmental Specification
|A
|Standard
|
|}


The alternative (and past front-runner).
==== Prior Considerations ====


==== Automation Direct GS4-2015 ====
VFDs from various manufacturers were considered during the evaluation process.  In particular, the following other drives were evaluated:


Not presently being considered.
* ABB ACS310-03U-50A8-2+J400
 
* Automation Direct GS23-2015
* Substantially larger: 12.60" L x 7.48" W x 7.48" D (versus 8.15" L x 4.29" W x 6.06" D for the GS3).
* Automation Direct GS4-2015
* Support for 1-phase operation (not needed for this application).
* Slightly reduced CT/VT ratings: 47A/49A vs. 49A/51A for the GS23.
* Slightly worse low temperature rating: -10 &deg;C vs. -20 &deg;C for the GS23 (not an issue).
* No FOC or torque control mode?
* No USB port?
* Slightly more/better analog/digital I/O options vs. the GS23 (not needed for this application).
* Might not be compatible with permanent magnet AC motors?
 
==== ABB ACS310-03U-50A8-2+J400 ====
 
Not presently being considered.


=== Line Reactor ===
=== Line Reactor ===
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A 3% impedance reactor absorbs transients and prevents nuisance tripping of drives in most applications and is typical for the line side.  A 5% impedance reactor can be used if the harmonic content is severe or if IEEE519 recommendations should be met.  The reactor impedance magnitude is said to be equal to the voltage drop.
A 3% impedance reactor absorbs transients and prevents nuisance tripping of drives in most applications and is typical for the line side.  A 5% impedance reactor can be used if the harmonic content is severe or if IEEE519 recommendations should be met.  The reactor impedance magnitude is said to be equal to the voltage drop.


For 37 FLA (motor rating).  Assume the VFD has about 97% efficiency (given loss is 391 W @  
For 37 FLA (motor rating).  Assume the VFD has about 97% efficiency (given loss is 391 W @ 42 A).


{| class="wikitable"
{| class="wikitable"
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* SAB Cable 08610804 8/4 THHN VFD Cable (eBay option).
* SAB Cable 08610804 8/4 THHN VFD Cable (eBay option).
=== Thermal Considerations ===
According to the datasheet, the Yaskawa GA50U2042ABA dissipates 391 W @ 42 A.  Assuming operation at 37 A, and an approximately linear decrease is power dissipation, up to 344 W of power dissipation is expected.  The drive is specified to operate (without de-rating) at up to 50 &deg;C (122 &deg;F).  Assuming that the pump house may reach temperatures exceeding 90 &deg;F, thermal rise must be kept to a minimum.  Assume that no more than 10 &deg;F of temperature rise is allowed (112 &deg;F ambient).
Using the formula: CFM = (3.17 * P) / dT (where dT is in &deg;F), CFM = 3.17 * 344 W / 10 &deg;F; 109 CFM.
The line reactor dissipates considerably less.  Exact dissipation is TBD; conservatively assume 67 W (KDRD24L value @ 48 A = 85 W; 85 W * 38 A / 48 A = 67 W).  CFM = 3.17 * 67 W / 10 &deg;F; 21 CFM.


=== Bypass ===
=== Bypass ===
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