View Question
Q: calculate rpm for two hydraulicly driven motors with given information ( Answered ,   0 Comments )
 Question
 Subject: calculate rpm for two hydraulicly driven motors with given information Category: Science > Physics Asked by: ptonyc-ga List Price: \$10.00 Posted: 23 Mar 2005 11:41 PST Expires: 22 Apr 2005 12:41 PDT Question ID: 499272
 ```Determine the maximum speed in rpm of two hydraulicly powered motors A , B using the following information: Electric motor that drives hydraulic pump rpm = 1750 Electric motor drive pulley = 3 3/4" diameter Hydraulic pump displacement = 6.0 GPM @ 1200 rpm Hydraulic pump pulley = 5 1/4" diameter Motor A displacement = 10 cu inches Motor B displacement = 3 cu inches I need to find: Motor A max rpm___________ Motor B max rpm___________```
 ```Hello ptonyc, here is the solution you require: First we must determine the speed at which the pumps are driven. RPM of pump = 1750 x (3.75/5.25) = 1250 Since the 6.0 GPM is given at 1200 RPM we must calculate the delivery rate at 1250 RPM. GPM of pump = (1250/1200) x 6.0 = 6.25 GPM Converting GPM to cubic inches per minute. 6.25 gal/minute x 231 cubic inches/gal = 1,444 cubic inches per minute Now we can calculate the RPM of the two motors. Motor A: 1,444 / 10 cubic inches per revolution = 144 RPM Motor B: 1,444 / 3 cubic inches per revolution = 481 RPM Please let me know if you don't understand anything I have done. Ask for a clarification and I will try and explain further. Redhoss```
 ptonyc-ga rated this answer: and gave an additional tip of: \$10.00 ```We are setting up the said pumps and motors and will test final rpm with a hand tachometer on Saturday, March 26, I will advise what actual hand tach tests out at. I don't know if your calculations will come out correct but I do believe it will be close. Thank you so much!```