H = head, (ft lb)/lb. The watt is also a unit of power. One of my first favorite cars was an MG TD which was honest enough to list both values. Butterworth Heinemann. Used to describe the rotation of an impeller. Calculating Horsepower from Torque. Its published numbers are as follows: HP = 426 bhp @ 5,900 rpm Torque = 420 ft-lbs @ 4,600 rpm. pres. Torque is measured in pound-feet (lb-ft.) Step 1. Motor Sizing. To calculate the size of a motor two methods can be used: The steady state method and the dynamic method. It's Calculated hp was given as 54.4 hp, while it's delivered hp (brake hp) was given as 10.97 hp. hp Horsepower. H2O) Round Duct Equivelent of Rectangular Duct: First Side of Rectangular Duct (in. To find the electric horsepower of a motor, use the equation: Horsepower = (Volts x Amps) / 745.7 (does not take efficiency into consideration) Example: The electric horsepower of a motor with 120 volts and 10 amps is: HP = (120 x 10) / 745.7. Water): Static Fan Efficiency (%): Brake Horsepower (HP): Air Density: Barometric Pressure (in Hg): Temperature (F) Density (lb/Cu.ft. Horsepower of reciprocating engines, particularly in the larger sizes, is often expressed as indicated horsepower, which is determined from the pressure in the cylinders. Brake horsepower and fan curves with direct drive motors. Below, I will discuss how to select a constant and variable volume fan based on our calculated brake horsepower. TS Tip Speed. The conversion from watts to horsepower is 745.7 watts = 1 hp. Class of fan. For an electric motor, brake horse power is the mechanical horsepower available at the shaft at specified rpm and full load current. Bhp = brake or shaft horsepower, bhp. Choose either Brushed or Brushless motor to get the most accurate result. Since motors are not 100% efficient, the number of amps needed to achieve the power output is actually higher depending on the efficiency. This calculator provides an estimate of the horsepower of an electric motor. A measure of power consumption. All you can do is measure the current fan and it is a four blade 18” fan with a 30 degree angle. Horsepower out is less than HP in, regardless of units. In one of my project for selection of the pump, I know following things : (1) my motor HP required is 50 (2) my brake HP is depending on flowrate and head varies between 30-40. Used to determine the proper motor horsepower and wiring. 1994. These formulas should be used as an estimate and for information only. That's how we spcecify motors - output horsepower in HP (US) or kW (Euro), where 0.746kW=1 HP. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0 2 4 6 8 1012 1416 18 CFM x 100 0 0.05 0.1 0.15 0.2 0.25 0.3 Brake Horse Power Brake Horsepower Curve (CFM to BHP relationship) This work is calculated without the consideration of the effects of any auxiliary component, that may slow down the actual speed of the motor. When calculating this, you will be able to determine the power that a fan requires theoretically, but you must be aware that the actual power that the fan requires (called brake horsepower) will always be greater than what you calculated simply because no fan can achieve perfect efficiency. Measure of fan speed. In addition to the information below for properly sizing a motor, Oriental Motor offers online motor sizing tools as well as assistance from our Technical Support staff. Once you select your CFM, draw a line vertically up to intersect the CFM vs SP Curves that run from lower right to upper left. fan laws for troubleshooting. D = impeller diameter or rotor, ft del. A value of 0.9 is often used for this calculation. Horsepower on the motor nameplate is the ideal steady-State shaft horsepower to an ideal load, at ideal temperature, at ideal voltage, at full-load-amperage (FLA). There are many different standards and types of horsepower. Brake horsepower is less than the advertised engine horsepower which excludes all loads such as water pumps, alternators, fans, transmissions, etc. Two common definitions used today are the mechanical horsepower (or imperial horsepower), which is about 745.7 watts, and the metric horsepower, which is approximately 735.5 … brake horsepower: NPSH = net positive suction head: V = velocity of fluid or liquid: p = impeller inlet pressure: p v = vapor pressure of fluid or liquid: SW = specific weight of fluid or liquid: g = acceleration of gravity: References - Books: 1) P. Aarne Vesilind, J. Jeffrey Peirce and Ruth F. Weiner. Other articles where Brake horsepower is discussed: horsepower: …turbine, or motor is termed brake horsepower or shaft horsepower, depending on what kind of instrument is used to measure it. If the power peak is really 5,900 rpm, how much torque is the engine generating at that engine speed? I have confusion in power calculation for the pump. ft.) Velocity Pressure (in. Calculate the length of the motor's lever arm from the data you have. 1 mechanical HP is equivalent to @ 746 watts. Firstly, it can help you segment the market better. If the resistance works out to be greater than the minimum value, use the value calculated. ): Velocity Pressure: Flowrate (CFM): Cross Sectional Flow Area (sq. This calculator can be used to determine the centrifugal pump brake horsepower (BHP) for a given flow rate (Q), head (H), specific gravity (S.G.), and efficiency (Eff). HBhp = hydraulic brake horsepower required by pump (pump efficiency = 1.0 for HBHP calculation) Also included is information on motor efficiency and horsepower calculations as well as several motor calculations for energy efficiency and electrical troubleshooting. If you enter any four of these variables as inputs, the calculator will determine the fifth variable. Watts = Horsepower × 746. rpm Revolutions Per Minute. BHP Brake horsepower, the fan’s power consumption. Motor Watts is the rated Watts of the motor. Pump-motor horsepower calculations Horsepower calculation—US units Calculate motor horsepower for shipboard auxiliary equipment such as pumps. The Fan Laws Applied A set of mathematical relationships called the fan laws governs the pulley sizes, rpm of each pulley, and the quantity of air in cfm. I know that Motor HP is the indicator for power consumption/energy bill when running the pump. Proper sizing and selection of a motor for your equipment is key to ensuring performance, reliability and cost of the equipment. Though horsepower units are a derivative of the 33,000 ft-lbf/min, it is not critical to understanding how to calculate motor horsepower for speed and torque. Brake horsepower definition: the rate at which an engine does work, expressed in horsepower . Motor Power is the Horsepower of the motor. Since 1 HP is equal to 746 W simply multiply the horsepower by 746 for this conversion. Horsepower (hp) is a unit of measurement of power, or the rate at which work is done, usually in reference to the output of engines or motors. 3rd ed. By definition horsepower is equal to 550 ft-lb per second or 33,000 ft-lb per minute. Brake horsepower (BHP) refers to the actual mechanical horsepower received at the shaft of the driven machine, such as a fan, pump, compressor, etc. Open: Electric Motor Time to Start Calculator. If you are a sales guy, with a good understanding of these terms, you have better chances of closing a deal, irrespective of whether you are selling or leasing cars for several reasons. Environmental Engineering. AMCA Air Movement & Control Association. CCW Counterclockwise. D s = specific diameter, ft. EFF = pump efficiency. Another common unit of power that motors are rated in is watts. HOW TO READ A FAN CURVE STEP 1 – SELECT YOUR DESIRED CFM . Rotation is determined by viewing the impeller from the drive side on centrifugal fans. Calculated out this gives an electric horsepower of 1.6092. It is always best to check the specs on the fan blade before replacing the condenser fan motor on any unit, and especially on older models. During the preliminary stages of your HVAC design, we can estimate the brake horsepower of a fan using the below formulas and rules of thumb. Brake horsepower (BHP) is the amount of work generated by a motor under ideal conditions. In order to accurately determine the brake horsepower, you will have to test the fan. Now let’s calculate some basic torque and horsepower numbers. The length should be expressed in feet, which may involve converting the units from meters. Again we’ll use our 2010 Camaro SS as a basis for our calculations. The first level of compliance requires the proposed brake HP be less than or equal to a calculated maximum allowed brake HP. Does anyone have any information regarding brake HP and direct drive motors? The second curve shows the relationship between the fan’s air volume flow rate and the brake horsepower. Details on fan type and control, air volume (CFM), brake horsepower, and motor nameplate horsepower for each fan in the fan system must be entered. Bhp Brake Horsepower. The speed of the tip of a fan wheel or prop measured in feet per minute. Account for Efficiency. In our example, we’ve chosen 33,000 CFM, marked with a brown vertical line. C = constant. The class identifies the limit of the fan’s performance range. CFM Cubic feet per minute, the volume of air moved per minute. It is measured by the... | Meaning, pronunciation, translations and examples I've used the formula (measured amps divided by fla) times horsepower of motor to plot cfm on a fan curve before, but I have been questioned by a customer regarding this formula and direct drive motors. Car and truck engines in Europe are rated in kW too. BHP is measured within the engine’s output shaft, and was originally designed to calculate and compare the output of steam engines. BHP = Brake Horsepower in Horsepower Q = Flow Rate in gallons per minute P = Pressure in pounds per square inch n = Efficiency expressed as a decimal value* *Many positive displacement pumps are assumed to operate at 90% efficiency. CW Clockwise. Fan Brake Horsepower: Flowrate (CFM): Static Pressure at Discharge (in. It was originally coined by a Scottish engineer to compare the power of steam engines with the power of horses. dynamic braking resistor selection calculation ... these calculations do not include the motor and drive losses which can easily be 10% of the motor horsepower. CL. Excellent question and a source of confusion for lots of new plant engineers. Horsepower is a unit of measurement that calculates power. In this case, the original was a four blade 18” fan with a 27 degree angle – but you don’t know that. gpm = fluid flow rate through pump. Used to indicate a fan’s motor size. Where: T = Time to Start (seconds) N = Velocity at load (rpm) T a = Average Torque During start (ft-lbs) W = Weight (lbs) R = Radius of Gyration (ft 2) [WR 2 = Rotating Inertia (lbs-ft 3)] 308 = Constant derived converting minutes to seconds, mass from weight, and radius to circumference. Since the power delivered by engine is calculated by applying brakes, it is popularly called has brake horsepower. This article will show you how to calculate the horsepower of your cars engine, an electric motor, and your own body. = pump delivery pressure, psia. Torque also has a direct influence on a vehicle's horsepower, since horsepower is simply a measure of how fast the motor's torque is being applied. Power consumption/energy bill when running the pump spcecify motors - output horsepower in HP ( brake HP less. 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