Variable Speed Drive
Substantial Electrical Energy Savings- NEMA 12 Packaging
- Built in “DC Link” Line Reactor for reduced electrical system total harmonics distortion (THD)
- “Soft Turn On” IGBT Transistors for reduced motor stress (insulation failure)
- Accepts “STEP” Speed Increase from 0 to 100% without tripping
Overview
UtilitySaver and BurnerMate Combustion Control Systems use Variable Speed Drives to provide variable speed fan combustion air flow control. Fan speed control minimizes damper pressure drop related to fan power usage. Variable speed fan control is a proven electrical energy savings technique that has been applied to thousands of HVAC installations.
VSD Kit
The VSD Kit includes a microprocessor-based VSD drive with a NEMA 12 enclosure and three (3) high speed semiconductor fuses and fuse holders. Fuses are included to replace the existing motor fuses and should be mounted in existing Motor Starter Panel.
Standard Equipment
- VSD with NEMA 12 Enclosure
- VSD semi-conductor fuses and fuse holder(s) (shipped loose for mounting in existing motor starter enclosure or VSD Bypass kit fuse enclosure)
Mounting Kit
The VSD mounting kit includes unistrut, brackets, and mounting plate sized for one VSD. Parts are shipped loose for field assembly. The UtilitySaver Mounting Kit is sized for mounting the UtilitySaver Panel and VSD Bypass Transfer Switch.
VSD Bypass Kit
The VSD Bypass Kit allows the boiler operator to change from variable speed to constant speed control by a simple control switch selection. Both full speed and variable speed operation are pre-set in the PCC-III controller configuration. The following equipment is included:
- Three (3) phase transfer switch with NEMA 12 enclosure
- High speed semi-conductor fuse with NEMA 12 enclosure
- Three (3) phase distribution terminal block (shipped loose for mounting in the existing motor starter enclosure)
Specifications
| Enclosure: | NEMA 12 |
| Humidity: | 95% non-condensing for operating, 93 % for storage/transport |
| Efficiency: | 95 - 97 % |
| Type: | Pulse Width Modulation (PWM) |
| Control Method: | “Soft Turn-On” IGBT PWM for dV/dt reduction |
| Protection: | Thermal overload, short-circuiting, ground fault, motor phase is missing, over temperature, high and low voltage and Total Harmonic Distortion (THD) protection built in. High speed, semiconductor fuses external. |
| Optional Bypass: | Full Speed / Variable Speed, 3 Phase Transfer Switch, NEMA 12 enclosure |
| Input: | 4-20 mAdc |
| Feedback: | 4-20 mAdc |
| Auxiliary Contacts: | No Fault and Running |
VSD Selection
When ordering please verify that the VSD Hp that you have selected is the correct size for your installation. Here are some of the guideline:
- VSDs derate as ambient temperature rises.
- For the ambient conditions expected, use the table below to compare Maximum Continuous Amps to the motor Nameplate Full Load Amps (FLA).
- If the motor FLA are lower, your VSD selection is correct. If the motor FLA are larger than the VSD Maximum Continuous Amps, select the next larger VSD size.
- On retrofit applications, actual motor amps can be measured.
- Fan motor amps at high fire are typically lower than motor FLA.
Measure the FD fan motor amps with the flame ON and at high fire to determine if a larger VSD size is actually required (do not measure during purge)
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Ordering Information
The VSD Kit includes VSD, Fuses and fuse holder(s). However, these parts must be listed separately when ordering:
- Specify the VSD Catalog Number that provides the required Voltage, Hp and Maximum Continuous Amps
- Specify the fuses and fuse holder(s) quantity and catalog numbers (note: below 65 amps (1) three pole fuse holder is required above 65 amps (3) single pole fuse holders are required)