Brigde Crane calculation
Brigde Crane calculation
(OP)
I posted this thread in the electric motor forum but got none replies so I am posting it again here. Thanks!
I need to calculate the electric motor and speed reducer for a small bridge crane. Its been very long since I have done this type of work and I not sure how to do it
Max crane load will be 2500 kg
Bridge crane weight 500 kg aprox
Number of wheels 4
Wheel diameter 132 mm
Speed 0,3 m/s
The motor and reducer will move with a chain drive a long shaft (5 meters) that connects 2 of the wheels
Any help please?
lukin1977
I need to calculate the electric motor and speed reducer for a small bridge crane. Its been very long since I have done this type of work and I not sure how to do it
Max crane load will be 2500 kg
Bridge crane weight 500 kg aprox
Number of wheels 4
Wheel diameter 132 mm
Speed 0,3 m/s
The motor and reducer will move with a chain drive a long shaft (5 meters) that connects 2 of the wheels
Any help please?
lukin1977





RE: Brigde Crane calculation
This is not a clear question. What does the motor do? What allows the motor to lift stuff?
--
JHG
RE: Brigde Crane calculation
I think basically you have to decide how big a piece of dirt the wheels have to ride over.
... or just look in anyone's catalog and use that number.
Mike Halloran
Pembroke Pines, FL, USA
RE: Brigde Crane calculation
Mike: I dont understand your comment about the piece of dirt. Could you explain?
RE: Brigde Crane calculation
RE: Brigde Crane calculation
RE: Brigde Crane calculation
Load = 2500+500 = 3000 kgf = 29419,95 N
wheel rpm = v/r = 0,3x2/0,132 = 4,54 rad/s = 43,14 rpm
i= motor rpm/wheel rpm = 1745/43.14 = 40,2
Friction force = Load x Us
Torque = Friction force x wheel diam /2 = Load x Us x wheel diam/ 2 Us = static friction coeff for steel = 0,4
Torque = 29419,95 x 0,4 x 0,132/ 2= 776,68 N.m
motor torque = 776,68 / 40,2 = 19,32 N.m
motor Power = 19,32 x 1745 x 0,1047 = 3529,89 W
3,5 kW seems too big to me
what am I missing?
RE: Brigde Crane calculation
The difference, however, is that I put a 50mm dia. bushing in the wheels and that's what generates the friction opposing the motion.
RE: Brigde Crane calculation
the two motorized wheels do not have a bearing of 50 mm. They have a keyed shaft
the remaining two wheels have a bronze bearing diameter 30 mm
RE: Brigde Crane calculation