Setup Variables - Justifying our 40hp Choice
Waste Water Evaporation Water Treatment Water Mister System
Why do we use a 40hp Motor in our Evaporators?
This Premium Efficient 841 Plus Motor is remanufactured for Slimline Manufacturing Limited. To new exacting standards. We add over $700.00 worth of proprietary items to ensure our units stand up to the most severe conditions. This severe duty motor was originally developed for applications in petrol-chemical, pulp and paper plants. With our proprietary additions it is specially adapted for the use in the Turbo-mist Evaporator, the dual inpro seal system and the upgrading of all exterior joints is crucial in the success of the evaporator durability
The 841 plus exceeds IEEE 841, Espact “92” and NRCan efficiency legislation has been brought to a new level of severe applications standards. The following is just of few of the standards features of the Slimline 841 Plus:
841+Exceeds IEEE 841, Exceeds EPACT “92” and NRCAN efficiency legislation.
Fully complies with NEMA MG-1 Part 31 specifications for INVERTER DUTY MOTORS 1.15SF on sine wave power (1.0 SF on inverter power).
40 C ambient NEMA design B, Class F insulation.
Class B rise at full load on sine wave, Regreasable bearing, and internal bearing.
All grease ports have been extended for simplicity of greasing.
All grease clean outs have been extended for easy access.
Suitable for 10:1 variable torque and 5:1 constant torque on inverter power.
Precision balanced rotors to -0.08 in/sec vibration, 0.005 in foot flatness form mounting hole to mounting hole. Conduit boxes twice NEMA volume standards. All cast iron construction.
Paint with stands 250 hr. salt spray test
Inpro Seals on both drive and non-drive ends
In EXTREME DUTY SITUATIONS an optional 316 stainless steel shaft is available
WHY DO WE USE A 40 HORSEPOWER MOTOR TO POWER OUR EVAPORATOR?
Why do we use a 40hp Motor in our Evaporators
Following is Slimline Manufacturing Ltd’s answer to questions and an attempt to address any concerns about the fact we utilize a 40 horse power electric motor which is purposely oversized for many reasons , following is our presidents explanation of his reasoning regarding this issue
Kim Blagborne, President & CEO of Slimline Manufacturing Ltd
“We had a chart recorder test ran on our evaporator and found the amperage draw during operation was 23.8 amperes on average with 446.8 volts. US Electric Motors publish the efficiency of their motor and these three factors were utilized in the following formula to determine the horsepower requirements to run our evaporator.
Using the formula for 3-phase power it provides us with the following info:
Using the efficiency factor published by US Electric Motors, at 50% load the motor has an efficiency rate of 94.2 % (Available direct from US Electrics)
Formula used: Horse power = (1.732 x Volts x Amps
Efficiency x Power Factor)/746
Horse power = (1.732 x 446.8 x 23.8 x .942 x .99)/746
The calculation results in an actual Horse power demand of 23 hp
Regarding the development and choice of running a 40-horse power in comparison to a 25-horse power motor, I offer the EASA technical Manual information with the effects of unbalanced voltages. As you read the technical paper you will find out how the effect of unbalance voltage affects the durability, reliability and operational costs. Nema recommends that voltage unbalance should not exceed 1 percent. Technical Paper 3.8 pages 3 – 68 & 3 – 69 explains in more detail the effects and results of unbalance voltages on 3 phase motors (following page).
The second major consideration is operating temperature. By rule of thumb, a machine’s life is cut in half for every 10 degree C rise, above its rated operating temperature.
Not only did I have to worry about unbalance voltage problems we have the issue of elevation change for different installations. The effects of elevation change can be calculated by the attached Technical Paper Section 3 pages 3 – 39
Then, I look at the effect ambient temperature in relations to durability reliability and operation costs. On Technical paper dealing with the Cause and Analysis of Stator and Rotor Failures in AC Induction Machines (Tech Note No.31) pages TN31-2 & TN31-3.
If you look at Table 1 AMBIENT TEMPERATURE VS. INSULATION LIFE it illustrates the effects of ambient temperature at various temperatures and the effects of Insulation life. This is why I installed the roof that provides shading on our evaporator, to minimize the effects from direct sunlight and provides protection from over spray gathering in the cooling vanes. In a condition where the Evaporator is blowing directly in the direction of the prevailing winds and the contaminated water is cycling through the blower. I also did not want to cover the motor totally, because I want to use the air movement cause by the intake of the Evaporator fan. This paper also discuss the effects thermal stress, overloading, Unbalance Phase Voltage, Obstructed Ventilation’s.
Keeping all of this in mind I must shoot for the highest overall efficiency to minimize my operational costs. By choosing a motor that is only operating at 50% of available load it gives me a efficiency factor of 94.2 percent, but protects me for the aforementioned problems of improper motor installations. This also protects my customer for being billed high rates from power companies for poor efficiency motors.
If you remember I have stated that I customize the motor for our installation, the reason for doing this are explained in The Cause and Analysis of Stator Failure under the Sub Title B. Tracking. This is why we take the time to seal the motor up as much as possible before we install it on the Evaporator unit. I trust this answers the question of why I choose to install a motor that is substantial over sized with respect to horsepower demand. If not please ask as many question, as you like, I am happy to explain and justify my decisions.
Some Customers ask about the cost saving of purchasing a 25-horse power motor compared to our 40-horse power motor. The suggested retail price list for the motors in question, a 40 horse power motor 1800 rpm has a suggested retail of $3,388.00 and the similar motor but 25 horse power is $2,194.00 each. Therefore, resulting in a price differential of $1,194.00.
For a difference of a $1,100 dollars the benefit of the 40 horsepower with respect to temperature effect, voltage variance and the power efficiency far out way the cost differential. With regards to the benefits of durability, reliability, cost of operations and not to forget customer satisfaction and my company’s reputation”.
Kim Blagborne, adds “ I would hope most of our customers compare fairly our product to other products and make an educated decision, we believe they are looking to us for a recommendation that will solve a problem, we recommend the best motor for this application is our 40 horsepower unit.”