Pool Main Pump Motor: Difference between revisions
→VFD Unit
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=== Starting and Stopping === | === Starting and Stopping === | ||
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 === | ||
Prior to the spring of 2022, pump flow was manually adjusted via the butterfly valve on the output side of the pump. | |||
Flow adjustment will be automatic with the VFD (details to follow). | |||
== Maintenance == | == Maintenance == | ||
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== Wiring and Fuse Protection == | == Wiring and Fuse Protection == | ||
The motor is supplied 3-phase "high-leg delta" 240 VAC. This is an asymmetrical supply (relative to earth ground); see measurements in the [[#Appendix|appendix]]. There are two disconnects: one in the basement of the | The motor is supplied 3-phase "high-leg delta" 240 VAC. This is an asymmetrical supply (relative to earth ground); see measurements in the [[#Appendix|appendix]]. There are two disconnects: one in the basement of the clubhouse (fused at 100 A) and one in the pump house (fused at 60 A). See the [[Electrical System]] diagram for details. | ||
The existing motor is fed by 3 x TBD (#10 AWG GND). Fused with 3 x FRN-R-60 (60 A) fuses. | The existing motor is fed by 3 x TBD (#10 AWG GND). Fused with 3 x FRN-R-60 (60 A) fuses. | ||
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== Variable Frequency Drive == | == Variable Frequency Drive == | ||
=== Background === | |||
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. | |||
Benefits to changing to the VFD include: | Benefits to changing to the VFD include: | ||
* | * 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 ( | * 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. | * 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: | ||
* | * The material cost (see the [[#Bill of Materials|bill of materials]]). This is managed by creative purchasing - utilizing refurbished and surplus materials where possible. | ||
* | * 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. | ||
=== Theory of Operation === | === Theory of Operation === | ||
The sections | NOTE: The sections that follow are still under development. | ||
==== Reset ==== | ==== Reset ==== | ||
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=== VFD Unit === | === VFD Unit === | ||
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. | |||
Yaskawa GA50U2042ABA: | |||
* 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. | ||
== | {| 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 | |||
| | |||
|} | |||
==== Prior Considerations ==== | |||
VFDs from various manufacturers were considered during the evaluation process. In particular, the following other drives were evaluated: | |||
* ABB ACS310-03U-50A8-2+J400 | |||
* Automation Direct GS23-2015 | |||
* Automation Direct GS4-2015 | |||
=== Line Reactor === | |||
<b><i>This section is currently being revised.</i></b> | |||
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 @ 42 A). | |||
Automation Direct | {| class="wikitable" | ||
!Manufacturer | |||
!Part Number | |||
!Dimensions | |||
!Rated<br>Voltage | |||
!Rated<br>Current | |||
!Impedance | |||
!Estimated<br>Cost | |||
!Comment(s) | |||
|- | |||
|Automation Direct | |||
|LR-2015 | |||
|4.25" H x 7.2" W x 4.75" D | |||
|208/240 V | |||
|46.2 A | |||
|0.22 mH<br>(rated) | |||
|$179 | |||
|Recommended for the LR-2015. | |||
|- | |||
|MTE | |||
|RL-04501 | |||
|4.60" H x 8.91" W x 7.13" D | |||
| | |||
|45 A | |||
|0.300 mH<br>(rated) | |||
|$289.31 (Galco) | |||
|Very large physical dimensions. | |||
|- | |||
|TCI | |||
|KDRD2L | |||
| | |||
| | |||
|40 A | |||
| | |||
|- | |||
|TCI | |||
|KDRULD42L | |||
| | |||
|600 V | |||
|32 A | |||
|0.861 mH<br>(calculated) | |||
| | |||
|3% @ 575/600V | |||
|- | |||
|TCI | |||
|KLR35BTB | |||
| | |||
|480 V | |||
|35 A | |||
|0.315 mH<br>(calculated) | |||
| | |||
|1.5% @ 480V (0.315 mH), 3% @ 240V | |||
|- | |||
|TCI | |||
|KLR45BTB | |||
| | |||
|480 V | |||
|45 A | |||
|0.490 mH<br>(calculated) | |||
| | |||
|3% @ 480V | |||
|- | |||
|TCI | |||
|KDRULD2L | |||
| | |||
|} | |||
* MTE RLW-004601 (42 A, 3.68" H x 6.00" W x 5.76" D). Not readily available. | * MTE RLW-004601 (42 A, 3.68" H x 6.00" W x 5.76" D). Not readily available. | ||
* TCI KDRD24L (208/240 VAC 48 A 15 HP, 3-phase, 3% - Low Z, 3.82" H x 6.95" W x 5.57" D). $195.94 on Galco (eBay TBD). | * TCI KDRD24L (208/240 VAC 48 A 15 HP, 3-phase, 3% - Low Z, 3.82" H x 6.95" W x 5.57" D). $195.94 on Galco (eBay TBD). | ||
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|$150 | |$150 | ||
|$300 | |$300 | ||
|Based on $206.25/ea @ Zoro w/ 20% discount. | |Based on $206.25/ea @ Zoro w/ 20% discount.<br>Alternate: Q403018PCI (listed at $80 on eBay, 7-Feb-2022). | ||
|- | |- | ||
|2 | |2 | ||
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=== Motor Cable === | === Motor Cable === | ||
Distance from the presumed origin to the motor terminals is estimated at | Distance from the presumed origin to the motor terminals is estimated at 28 ft (55" mid motor starter to floor, 102" to north wall, 74" to motor horizontal, 92" pit ceiling to floor, 16" wall to motor junction box). | ||
Shielded VFD cabling may be required to contain high-frequency emissions. | Shielded VFD cabling may be required to contain high-frequency emissions. | ||
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* In January 2022, there appears to be a low-cost option (on eBay, Michigan-based seller) to purchase Lapp Kabel #760604 (4 x #6 AWG) VFD cable for less than $6/ft. This cable has an OD of 25.5 mm (1.00 inches). | * In January 2022, there appears to be a low-cost option (on eBay, Michigan-based seller) to purchase Lapp Kabel #760604 (4 x #6 AWG) VFD cable for less than $6/ft. This cable has an OD of 25.5 mm (1.00 inches). | ||
* 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 °C (122 °F). Assuming that the pump house may reach temperatures exceeding 90 °F, thermal rise must be kept to a minimum. Assume that no more than 10 °F of temperature rise is allowed (112 °F ambient). | |||
Using the formula: CFM = (3.17 * P) / dT (where dT is in °F), CFM = 3.17 * 344 W / 10 °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 °F; 21 CFM. | |||
=== Bypass === | === Bypass === | ||