New High-Efficiency Gearmotors Offer Energy Savings Over Worm Gear Drives
In 1992, Congress passed the Energy Policy and Conservation Act that imposes new efficiency requirements on manufacturers of electric motors, lamps, utility distribution transformers and luminaires. This also means that motor manufacturers will be required to produce general purpose single-speed motors that are more efficient, and use less energy than previous makes. This act, which demands compliance by October 1997, is also having a dramatic effect on power transmission manufacturers and their current gearmotor designs. Add to this new legislation, large incentives offered by power companies to customers using these new efficient motors, and it's easy to see that the future of power transmission products will be driven by the customer's need for more efficient, environmentally friendly products.
In this new climate of conservation and manufacturer's responsibility,
the Falk Ultramite® has
been developed as a new, high-efficiency gearmotor for a wide range of general purpose, factory, and low-horsepower power transmission applications.
The premise behind the Ultramite gearmotor is energy savings over the traditional worm gear drive. Unlike a worm gear drive, this gearmotor is designed to be lower in initial cost. Because the gear teeth are so efficient, the customer can specify a smaller horsepower, less expensive motor. The result is a product that is initially less expensive and saves a considerable amount of energy over long term service life.
Smaller, Lower Cost Motors
Because the Ultramite's gear teeth are more efficient than those on worm gear drives,
motor selections can be one size smaller. One size smaller motors can be used in over one-third of possible single reduction worm gear selections and the majority of double reduction worm-worm gear selections. This reduces the cost of the motor for the Ultramite system and may also increase motor efficiency if the smaller motor is operating closer to its full rating.
Substitutions, drop-in replacement and retrofits are made easy due to the Ultramite
gearmotor's base-mounted design that has a footprint that matches those of other
major manufacturers. A simple, plug-in and bolt-on design makes this new drive
compatible with standard, off-the-shelf NEMA and IEC C-face motors permitting
the use of customer-preferred brands. The Ultramite is available in several
sizes in the .25 HP (.25 kW) to 20 HP (15 kW) power range. (See figure 1., Smaller
Motors and figure 2., Motor Savings)
This isn't to say that worm gear drives are obsolete...they aren't. Worm gear drives are still well-suited to certain applications and are fairly cost-efficient and have acceptable reliability. Worm gear drives perform best in limited duty applications. For example, a good application for a worm gear drive would be raising and lowering a parking gate or an industrial garage door. However, worm gear drives are a poor choice where efficiency is required.
Long Term Energy Cost Savings
The Ultramite has an operating efficiency that is considerably higher than
a worm gear drive. The beveled, helical-toothed gearing is hardened to enhance
design efficiency and extend service life. The combination of the helical gearing
and smaller electric motor give the Ultramite a substantial operating cost savings.
(See figure 3., Efficiency Comparison)
Motor Efficiency
The aforementioned energy conservation laws are already affecting the way industry
buys. Even though the regulating agencies are not currently penalizing companies
for purchasing less efficient equipment, many companies are specifying the more
efficient equipment. (See figure 4., Average Motor Efficiency)
The energy cost savings the Ultramite provides is calculable. This can be figured two ways:
Long Method
The annual energy cost savings of an Ultramite drive over a worm gear drive can be calculated using this relatively complex formula:
Where:
| S = Annual Energy Cost Saving |
T = Operating Time (hrs/yr) |
| L = Demand Load (Output HP) |
em = Electric Motor Efficiency |
| .746 =
kW Per Horsepower |
ew = Worm Gear Drive Efficiency |
| R = Electrical Energy Rate |
eu = Ultramite Drive Efficiency |
Short Method
This calculation can be
simplified using appropriate charts to find values for factors:
S = (L) x
(C) x (D)
Where:
S = Annual Energy Cost Savings ($)
L =
Demand Load (Output HP) - (Refer to figure 5., Estimated Demand Load)
C = (.746)(R)(T)/em, (Refer to figure 6.,
Factor C)
D = [ 1/ew - 1/ew ] (Refer to Figure 7., Factor D)
Electrical Energy Rate
The electrical
energy rate ($/kW hr) for a particular industrial user, is equal to the
monthly electric utility bill, divided by the number of kilowatt hours
used during the month. Rates vary throughout the country and are based on
several different charges and rate structures. Consult the local power
utility for information.
Example - Energy Cost Savings
Calculate the
energy cost savings to replace a worm gear drive with an Ultramite drive
using the short method:
|
Worm Drive |
Ultramite |
| Demand Load |
1.3 HP |
1.3 HP |
| Duty Cycle |
6,000 Hrs/Yr |
6,000 Hrs/Yr |
| Energy Rate |
$.08/kWHr |
$.08/kWHr |
| Drive Size |
4.25" C.D. |
07UCB2 |
| Drive Ratio |
60:1 |
63:1 |
| Drive Efficiency |
65% |
97% |
| Motor Size |
2 HP |
1 HP |
| Motor Efficiency |
86.5% |
87.5% |
| System Efficiency |
56.2% |
84.9% |
| ENERGY COST
SAVINGS |
Year |
Annual |
Cumulative |
| S = (L) x (C) x (D) |
1 |
$273 |
$273 |
| S = (1.3) x ($414.20) x (.5075) |
2 |
$273 |
$564 |
| S = $273.20 |
3 |
$273 |
$820 |
|
4 |
$273 |
$1093 |
|
5 |
$273 |
$1366 |
|
