JasonPAtkins
Hot Rolled
- Joined
- Sep 30, 2010
- Location
- Guinea-Bissau, West Africa
Hey all, I have just enough experience to be dangerous in two areas that are coinciding in today's work.
I posted recently about the compressed adobe block making machine I have over here in West Africa. The Yanmar L70V6 diesel engine that runs it was abused by my (untrained) guys, and has seized. That motor has given me so much trouble over the years, and I now have good solar electricity, that I'm done with it and going to convert the machine to electric. I'll send a replacement Yanmar over eventually so it can still be mobile if the need arises.
Unfortunately, not having planned for this conversion right now, I'm digging through my spare parts bins to put something together, doing the best I can with what I have. Hence my current question.
The Yanmar was 6.5hp (4.9kw) at 3600rpm. The motor drives a two-stage hydraulic pump.
In my spares bin, I have Nord motors of both 2hp and 3hp. I would prefer to use the 3hp, because I'm not certain 2hp of electric motor is equivalent to 6.5hp of diesel. I know you need less electric, I'm not sure exactly how much less for hydraulics.
My current limitation, however, is that my biggest single phase (which is all I have available at that site currently) VFD is 2hp. (I don't have any single phase motors, or I'd use that and skip the VFD.) I need to fab and machine a mount for the motor, so I'd rather use the 3hp motor so that later when my power situation is upgraded to 3 phase, I can switch to a 3hp 3 phase VFD without also having to make a new motor mount and swap the motor.
I did some cursory searching and found people asking about using a higher rated motor than VFD (using it at the VFD rating) and there were some comments about surges causing problems. I'm wondering though, for driving a hydraulic pump where there's no braking, and where the speed ramp up and down can be slow, if that's still a problem? Would it be safe to use a 2hp VFD to drive a 3hp motor if the motor is powering a hydraulic pump, or is that likely to cause problems? (A further note, the hydraulic pump wants to spin fast, so whichever motor I use, I'll be driving a 1740rpm motor as fast as I can. The Nord motors are rated up close to 3000rpm. The pump wants 3600, but I think the difference might change my block cycle time from 15 seconds to 17 or something, which is totally acceptable. The pump is also a 3000psi pump and the most the machine actually needs to operate is 2500psi.)
I posted recently about the compressed adobe block making machine I have over here in West Africa. The Yanmar L70V6 diesel engine that runs it was abused by my (untrained) guys, and has seized. That motor has given me so much trouble over the years, and I now have good solar electricity, that I'm done with it and going to convert the machine to electric. I'll send a replacement Yanmar over eventually so it can still be mobile if the need arises.
Unfortunately, not having planned for this conversion right now, I'm digging through my spare parts bins to put something together, doing the best I can with what I have. Hence my current question.
The Yanmar was 6.5hp (4.9kw) at 3600rpm. The motor drives a two-stage hydraulic pump.
In my spares bin, I have Nord motors of both 2hp and 3hp. I would prefer to use the 3hp, because I'm not certain 2hp of electric motor is equivalent to 6.5hp of diesel. I know you need less electric, I'm not sure exactly how much less for hydraulics.
My current limitation, however, is that my biggest single phase (which is all I have available at that site currently) VFD is 2hp. (I don't have any single phase motors, or I'd use that and skip the VFD.) I need to fab and machine a mount for the motor, so I'd rather use the 3hp motor so that later when my power situation is upgraded to 3 phase, I can switch to a 3hp 3 phase VFD without also having to make a new motor mount and swap the motor.
I did some cursory searching and found people asking about using a higher rated motor than VFD (using it at the VFD rating) and there were some comments about surges causing problems. I'm wondering though, for driving a hydraulic pump where there's no braking, and where the speed ramp up and down can be slow, if that's still a problem? Would it be safe to use a 2hp VFD to drive a 3hp motor if the motor is powering a hydraulic pump, or is that likely to cause problems? (A further note, the hydraulic pump wants to spin fast, so whichever motor I use, I'll be driving a 1740rpm motor as fast as I can. The Nord motors are rated up close to 3000rpm. The pump wants 3600, but I think the difference might change my block cycle time from 15 seconds to 17 or something, which is totally acceptable. The pump is also a 3000psi pump and the most the machine actually needs to operate is 2500psi.)