Pool Main Pump Motor
The main pool pump motor at the facility (as of August 2021) is a Leeson Model C254T17DK13A (catalog #199987.00). It is rated for 15 HP (11 kW), 37 FLA @ 230 VAC. It is inverter duty rated (confirmed by the local manufacturer's rep) with a 10:1 PWM ratio (60 Hz, 1770 RPM down to 6 Hz, 177 RPM).
It has a month/year manufacturing designation of "H2016" - presumably corresponding with August (H=8) 2016. This makes sense, as the pump was noted to have been replaced in early 2017.
Flow Rate
The pump flow is adjusted via the butterfly valve on the outflow 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.
In the future, a VFD may be used to reduce the motor speed, eliminating the need for manual adjustment via a valve.
Wiring and Fuse Protection
The existing motor is fed by 3 x TBD (#10 AWG GND). Fused with 3 x FRN-R-60 (60 A) fuses.
Power Factor Correction Capacitor (PFCC)
At present (as of August 2021), no power factor correction capacitor (PFCC) is in use. It was decided that given cost priorities, a PFCC would not offer sufficient payback to justify its purchase.
Myron Zucker was contacted in August 2020 and provided two options, both rated for 240 VAC, 5 kVAr, 3-phase, 60 Hz:
- KNM23005-3 (NEMA 12 for indoor use, 14" H x 9.25" W x 5.25" D)
- KNM23005-3N3 (NEMA 3R suitable for outdoor use, 16" H x 12" W x 6" D)
Applying a 5 kVAr PFCC would reduce the FLA from 37 A to 31 A. This would reduce i-squared-R losses by 6 A. Actual losses are then based upon the cable run.
Variable Frequency Drive (VFD)
IMPORTANT: At this time, this section is for investigation purposes only. It has not been determined when/if a VFD will be implemented.
Requirements
- It's likely that the drive could be exposed to greater than 40 °C (104 °F) operation. A very hot summer day, plus additional heat contained within the building and/or enclosure could easily place the ambient operating range into the 40 °C to 50 °C (122 °F) range. This temperature is also referred to as the Maximum Enclosure Internal Temperature (MEIT) in some literature.
High-Leg Delta
A major issue/question remains to be answered: Can any VFD reliably operate with high-leg delta service as is present at the club?
Safety
A safety relay (reset and E-stop circuits) and additional contactor (maybe two contactors w/o STO) are likely required.
Options
The following options are under consideration (still a work in progress). All drives are sized to drive a 15 HP motor, 230 VAC three-phase.
Unless otherwise noted, all support Modbus RTU (via RS-485).
Fuji Electric FRN0047C2S-2U
- 47.0 FLA (21 % margin for 37 FLA)
- 10.24" H x 8.66" W x 7.48" D
- No STO
Hitachi WJ200-110LF
- 56.0 FLA VT (34 % margin for 37 FLA)
- 11.65" H x 7.09" W x 6.89" D
- With STO
- DC Reactor: DCL-L-11
- Input Side AC Reactor: ALI-22L2
- Input Side Noise Filter: NF-L60
- Radio Noise Filter: ZCL-A (Zero-Phase Reactor) or CFI-L (Capacitor Filter)
DURApulse GS20 Series GS23-2015 =
- 51 FLA VT (27 % margin for 37 FLA)
- Frame Size "E": 9.84" H x 5.12" W x 7.28" D
- With STO (TUV Certified)
- Conduit Box: GS20A-N1E ($29)
- EMC Filter & Zero-Phase Reactor: RF008X00A
- Input Fuse: 110 A, TJN110 (Fast-Acting Class T) or JHL110 (Edison Class J)
- Line/Load Reactor: LR-2020 ($181.00)
- AC Output Filter (VTF): VTF-246-NRS
Wiring
Shielded VFD cabling may be required to contain high-frequency emissions. Automation Direct has #8 AWG 4-conductor XLPE insulated shielded cable, rated for 50 A at 75 °C (NEC 310.15 (B), assumes 30 °C ambient) for $8.08/ft (August 2021 pricing). The cable is made in USA by Southwire. This cable has an OD of 0.87 inches and minimum bend radius of 10 inches. Calculations suggest a 1-1/4" conduit may be necessary to pull a cable of this diameter with adequate fill margin. The existing PVC conduit appears to be about 3/4" (to confirm), which would need to be replaced.
A load reactor likely will not be used, nor does it necessarily eliminate the need for shielded VFD cabling.
Configuration
Subject to further review:
- Variable Torque (VT) for pump control (power is proportional to the cube of the speed)
DURApulse GS23-2015
- For 75% load at 50 °C, no de-rating is necessary up to 4 kHz (SVPWM mode).