Can anyone tell me what a 50lb. thrust electric motor is equal to in horse power? Is there some type of table somewhere that shows these comparisons? I know they now have salt water electric motors, and was wondering how they compare? thanks
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Richard
Can't get there from here
You need to find out the wattage of the motor or how many AMPs it draws for a conversion to HP. example: Say the motor draws 25 amps at 12 v. 12x25=300 watts (assuming 100% efficiency, which you can't) HP= 300watts/746watts HP= .4hp They should have the answers at whatever store your shopping at...
You need to find out the wattage of the motor or how many AMPs it draws for a conversion to HP. example: Say the motor draws 25 amps at 12 v. 12x25=300 watts (assuming 100% efficiency, which you can't) HP= 300watts/746watts HP= .4hp They should have the answers at whatever store your shopping at...
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Dan McGuire
Trolling Motors
I own a 23 foot Venture Newport. It weighs 2000 lb. My 4.5HP Mercury will push the Newport at just over six knots. I have a 35 pound thrust trolling motor. It will push the boat at 3 knots when the battery is full. Since the drag goes up about as a square up to hull speed, a fifty pound thrust probably would not push it much faster. Maybe about 3.6 knots. The prop will also have an effect. I would bet, though, that a one or two horsepower OB would have about the same thrust. I really enjoy coming into the marina pushed by that silent trolling motor.
I own a 23 foot Venture Newport. It weighs 2000 lb. My 4.5HP Mercury will push the Newport at just over six knots. I have a 35 pound thrust trolling motor. It will push the boat at 3 knots when the battery is full. Since the drag goes up about as a square up to hull speed, a fifty pound thrust probably would not push it much faster. Maybe about 3.6 knots. The prop will also have an effect. I would bet, though, that a one or two horsepower OB would have about the same thrust. I really enjoy coming into the marina pushed by that silent trolling motor.
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Gord May
Torque to H.P.
Don't know if this helps, but: Torque in Inch Pounds of Force = (H.P. x 63025)/ Motor RPM 1 H.P. = 18 In. Lbs. Torque @ 3450 RPM or 37 In. Lbs. @ 1725 RPM Etc.
Don't know if this helps, but: Torque in Inch Pounds of Force = (H.P. x 63025)/ Motor RPM 1 H.P. = 18 In. Lbs. Torque @ 3450 RPM or 37 In. Lbs. @ 1725 RPM Etc.
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Tom
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Clyde
No correlation between lbs and horsepower!
There is no correlation between 50 lbs. thrust and Horsepower! Pound thrust is a static measurement in pounds of an electric outboard motor, horsepower is a measurement of "work" being performed. The two measurement systems are incompatible to each other, they can not be used to compare one against the other. The theoretical formula for power needed to move a displacement hull vessel like a sailboat in the water is in horsepower, you need to convert to horsepower. Richard is correct in his response, you need the Voltage, Amperes and electric motor Efficiency of an electric outboard motor to be able to compare it to Horsepower. Watts = Voltage x Amperes x Efficiency of electric motor(shown in %) and hp=745.7 Watts. The relationship between Torque and Horsepower is; Torque (ft-lbs)= (5252 x Horsepower)/RPM. Torque is in foot-pounds and thrust is in pounds. Torque is a dynamic measurement and thrust is a static measurement, they are not in the same measurement units. In Tom's response, if you go to the Ray Electric Motor's web site and look at the 270 lbs. thrust electric motor, its rated at 5 hp at 60 Volts and 84 Amps going at its top speed. If you do the math, the electric outboard motor is about 74% efficient. Running at its top rated speed at its highest horsepower output, 5 hp, the electric outboard motor is only good for 1.8 hours using ten golf cart batteries. The uses of pounds of thrust for electric outboard motors and horsepower for gas outboard motors have confused many people, it’s a Frequently Asked Question (FAQ), look at the Minnokota FAQ. Fair Winds, Clyde
There is no correlation between 50 lbs. thrust and Horsepower! Pound thrust is a static measurement in pounds of an electric outboard motor, horsepower is a measurement of "work" being performed. The two measurement systems are incompatible to each other, they can not be used to compare one against the other. The theoretical formula for power needed to move a displacement hull vessel like a sailboat in the water is in horsepower, you need to convert to horsepower. Richard is correct in his response, you need the Voltage, Amperes and electric motor Efficiency of an electric outboard motor to be able to compare it to Horsepower. Watts = Voltage x Amperes x Efficiency of electric motor(shown in %) and hp=745.7 Watts. The relationship between Torque and Horsepower is; Torque (ft-lbs)= (5252 x Horsepower)/RPM. Torque is in foot-pounds and thrust is in pounds. Torque is a dynamic measurement and thrust is a static measurement, they are not in the same measurement units. In Tom's response, if you go to the Ray Electric Motor's web site and look at the 270 lbs. thrust electric motor, its rated at 5 hp at 60 Volts and 84 Amps going at its top speed. If you do the math, the electric outboard motor is about 74% efficient. Running at its top rated speed at its highest horsepower output, 5 hp, the electric outboard motor is only good for 1.8 hours using ten golf cart batteries. The uses of pounds of thrust for electric outboard motors and horsepower for gas outboard motors have confused many people, it’s a Frequently Asked Question (FAQ), look at the Minnokota FAQ. Fair Winds, Clyde
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Dan McGuire
Final Answer On Thrust/Horsepower
Horsepower is a function of force times speed, but there is a way around this. I believe the answer he was looking for was what a 50lb thrust motor is similar to in a gas engine. A 50lb pound thrust motor will use about one amp at 12v or 600w. 600w is equal to just over .8hp. If you throw in an efficiency of roughly 75%, it is the equivalentof just over a 1hp motor. A good size battery (100AH) would run it for about two hour, but the thrust will steadily decrease to zero as the battery discharges.
Horsepower is a function of force times speed, but there is a way around this. I believe the answer he was looking for was what a 50lb thrust motor is similar to in a gas engine. A 50lb pound thrust motor will use about one amp at 12v or 600w. 600w is equal to just over .8hp. If you throw in an efficiency of roughly 75%, it is the equivalentof just over a 1hp motor. A good size battery (100AH) would run it for about two hour, but the thrust will steadily decrease to zero as the battery discharges.
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Clyde
No correlation between lbs thrust and Amperes.
One pound of thrust does not equal one Amp of current draw, its another misconception. There is no mathematical formula to relate pounds of thrust into current draw on an electric outboard motor. If you go to the Ray Electric Motor's web site and look at the 270 lbs. thrust electric motor, its rated at 5 hp at 60 Volts and 84 Amps going at its top speed with 74% efficiency. Assuming you use one amp for each pound of thrust at 74% efficiency, the horsepower output should have been 16 hp. The manufacturer had rated the electric outboard motor at 5 hp, which is not even close to 16 hp using one Amp for each pound of thrust. Fair Winds, Clyde
One pound of thrust does not equal one Amp of current draw, its another misconception. There is no mathematical formula to relate pounds of thrust into current draw on an electric outboard motor. If you go to the Ray Electric Motor's web site and look at the 270 lbs. thrust electric motor, its rated at 5 hp at 60 Volts and 84 Amps going at its top speed with 74% efficiency. Assuming you use one amp for each pound of thrust at 74% efficiency, the horsepower output should have been 16 hp. The manufacturer had rated the electric outboard motor at 5 hp, which is not even close to 16 hp using one Amp for each pound of thrust. Fair Winds, Clyde
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Dan McGuire
Is to a Relationship
The correlation of approximately 1a to 1lb of thrust only applies to 12v system. As you get to higher voltage systems the efficiency is better. The 270lb thrust system has a 5040w system. If you divide that by 12w or 1A X 12v, then you get approximately 420a (artificially changed 60v to 12v). 420/270 = 1.55a/lb. Go to a store that sells trolling motors and look at the smaller units (30 to 100lb thrust) and the relationship is pretty close to 1a per pound of thust. I believe the bottom line is tht the 50lb thrust motor is roughly equivalent to a .8 to a 1.0hp gas engine.
The correlation of approximately 1a to 1lb of thrust only applies to 12v system. As you get to higher voltage systems the efficiency is better. The 270lb thrust system has a 5040w system. If you divide that by 12w or 1A X 12v, then you get approximately 420a (artificially changed 60v to 12v). 420/270 = 1.55a/lb. Go to a store that sells trolling motors and look at the smaller units (30 to 100lb thrust) and the relationship is pretty close to 1a per pound of thust. I believe the bottom line is tht the 50lb thrust motor is roughly equivalent to a .8 to a 1.0hp gas engine.
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