I have considered downsizing the motor. I have also considered running a single phase motor. Both are more expensive than what I can purchase the 10 hp rotophase for. It is $400. I have been told I need at least a 10 gauge wire to the converter. Is this wire big enough? How many wires will it take? I have someone who knows what he is doing that will wire it but would like a head start on supplies. What size breaker? Is 50 amp big enough? Is it best to keep the converter close to the panel or the machine. What size wire from the converter to the machine?
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Need Help On Converter Choice.
- Thread starter Zachp
- Start date
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- Feb 2, 2013
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the choice seems rather simple from where i sit.
if i were in your shoes, i'd bite the bullet, and get the 10 hp rotophase and not look back.
but i'm not like most guys you'll meet.
if i were in your shoes, i'd bite the bullet, and get the 10 hp rotophase and not look back.
but i'm not like most guys you'll meet.
- Joined
- Feb 2, 2013
- Messages
- 3,627
i'd use 8 gauge for the short single phase 50 amp input wire run to the RPC, then you can use 10 gauge everywhere else as long as you aren't making long runs
F
Firestopper
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Sizing For Load Types
1.
Motor Loads
A...
TYPE 1 Motor Load:
May be used up to the HP rating of the converter.* For instant reversing (as for rigid tapping), size according to TYPE 3 LOADS
*Many restrictions apply. Most applications require sizing the converter a
minimum of 50% larger (see all load types).
B.
TYPE 2 Motor Load:
These include domestic & European lathes without a clutch, some pumps, wheel balancers, paper cutters, flywheel driven equipment, air conditioners, blowers, woodworking band saws, dough mixers, meat grinders, motors rated below 1000 RPM, etc. Use a converter with HP rating of at least 50% larger than HP of the motor. .
C.
TYPE 3 Motor Load:
These include Design "E" motors, Taiwanese, Chinese, Brazilian, Mexican motors, pumps starting under load, etc. Use a converter with twice the HP rating of the motor. .
D.
TYPE 4 Motor Load:
These include laundry extractors, hoists, elevators, etc. For these start-up loads use a converter with three times the HP rating of the motor. .
E.
TYPE 5 Motor Load:
Often hydraulic pumps, which come under a momentary load during use will be loaded well beyond their rated HP for the brief period of maximum PSI. Examples includes bailers, compactors, paper cutters, shears, pumps, etc. The HP of the converter must be at least as high as the actual HP developed by the motor. To calculate the HP developed, you must first find the actual amperage drawn during maximum PSI. This is different from the rated amps of the motor. Next you would divide the maximum amperage by 2.8 to find the actual HP being developed by the motor. That figure is the minimum size of converter to be used. Example: A 10 HP compactor with a motor rated at 28 amps but draws a peak of 40 amps momentarily at maximum compression. Divide 40 by 2.8 = 14.3 HP being developed, use model R-15 Rotary Converter.
2.
Resistive Loads
Resistive loads must use the Rotary type converter, the Static type should never be used because it would be damaged. There are two methods to determine the HP of the converter to be used. One method is to take the amperage rating of the equipment and divide by 2.8 to find the equivalent HP. The other method is to take the KW rating and multiply times 1.34 or divide by .75 to find the equivalent HP of the equipment.
3.
Computer, Rectifier & Transformer Loads
Transformers and electric equipment (welders, lasers, EDM machines, CNC equipment, computers, plating rectifiers, power supplies, etc.) can operate on the Rotary Converter. Use the same formula as for resistive loads to determine the proper size converter to use.
If a 4-wire wye input is required (all lines equal voltage to ground), a three phase delta-to-wye isolation transformer must be installed between the converter and the equipment to change the delta power to wye power.
4.
Multiple Motor Applications
Due to the high in-rush current required to start a motor (5 to 10 times the normal running current), most applications require sizing the HP of the Rotary Converter 50% larger, or more than the horsepower of the largest motor, or any combination of motors started at exactly the same time. The first motor started, if not running heavily loaded, generates additional 3-phase power back into the circuit. You can then run additional motors, provided they are not running heavily loaded and not all started at the same time. A maximum of up to 3 times the HP rating of the Rotary Converter can run at the same time, if not heavily loaded, and not started simultaneously. For example, a 30 HP Rotary Converter potentially could run motors totaling up to 90 HP. Contact factory for verification of sizing.
I found some interesting info on types of loads for determining Idler selection. I stand corrected on the minimum idler size. According to the type of load chart, most applications would require a Idler to be 50% larger than the highest HP in the system.
I ran #8 wire from panel (40amp breaker) to RPC, and used #8 for all machine feeds as they are long and can be extended to add machines. All machines have cord caps and receptacles. All larger machines have internal breakers to protect the machines. AC tends to be quite dirty and input voltage can vary thought the day. The Idler in our system is a Howell (very robust and heavy compared to other 7.5 3PH motors) continuous duty, RPM 1725, 21 amp @230 (lower as Idler) and SF of 1.15 . I have not experienced issues with this set up, even during the summer months when AC input is the dirtiest.
If you decide to mount your RPC, use vibration isolators to mount the Idler as this will prevent horrific harmonics, ask me how I know lol.
1.
Motor Loads
A...
TYPE 1 Motor Load:
May be used up to the HP rating of the converter.* For instant reversing (as for rigid tapping), size according to TYPE 3 LOADS
*Many restrictions apply. Most applications require sizing the converter a
minimum of 50% larger (see all load types).
B.
TYPE 2 Motor Load:
These include domestic & European lathes without a clutch, some pumps, wheel balancers, paper cutters, flywheel driven equipment, air conditioners, blowers, woodworking band saws, dough mixers, meat grinders, motors rated below 1000 RPM, etc. Use a converter with HP rating of at least 50% larger than HP of the motor. .
C.
TYPE 3 Motor Load:
These include Design "E" motors, Taiwanese, Chinese, Brazilian, Mexican motors, pumps starting under load, etc. Use a converter with twice the HP rating of the motor. .
D.
TYPE 4 Motor Load:
These include laundry extractors, hoists, elevators, etc. For these start-up loads use a converter with three times the HP rating of the motor. .
E.
TYPE 5 Motor Load:
Often hydraulic pumps, which come under a momentary load during use will be loaded well beyond their rated HP for the brief period of maximum PSI. Examples includes bailers, compactors, paper cutters, shears, pumps, etc. The HP of the converter must be at least as high as the actual HP developed by the motor. To calculate the HP developed, you must first find the actual amperage drawn during maximum PSI. This is different from the rated amps of the motor. Next you would divide the maximum amperage by 2.8 to find the actual HP being developed by the motor. That figure is the minimum size of converter to be used. Example: A 10 HP compactor with a motor rated at 28 amps but draws a peak of 40 amps momentarily at maximum compression. Divide 40 by 2.8 = 14.3 HP being developed, use model R-15 Rotary Converter.
2.
Resistive Loads
Resistive loads must use the Rotary type converter, the Static type should never be used because it would be damaged. There are two methods to determine the HP of the converter to be used. One method is to take the amperage rating of the equipment and divide by 2.8 to find the equivalent HP. The other method is to take the KW rating and multiply times 1.34 or divide by .75 to find the equivalent HP of the equipment.
3.
Computer, Rectifier & Transformer Loads
Transformers and electric equipment (welders, lasers, EDM machines, CNC equipment, computers, plating rectifiers, power supplies, etc.) can operate on the Rotary Converter. Use the same formula as for resistive loads to determine the proper size converter to use.
If a 4-wire wye input is required (all lines equal voltage to ground), a three phase delta-to-wye isolation transformer must be installed between the converter and the equipment to change the delta power to wye power.
4.
Multiple Motor Applications
Due to the high in-rush current required to start a motor (5 to 10 times the normal running current), most applications require sizing the HP of the Rotary Converter 50% larger, or more than the horsepower of the largest motor, or any combination of motors started at exactly the same time. The first motor started, if not running heavily loaded, generates additional 3-phase power back into the circuit. You can then run additional motors, provided they are not running heavily loaded and not all started at the same time. A maximum of up to 3 times the HP rating of the Rotary Converter can run at the same time, if not heavily loaded, and not started simultaneously. For example, a 30 HP Rotary Converter potentially could run motors totaling up to 90 HP. Contact factory for verification of sizing.
I found some interesting info on types of loads for determining Idler selection. I stand corrected on the minimum idler size. According to the type of load chart, most applications would require a Idler to be 50% larger than the highest HP in the system.
I ran #8 wire from panel (40amp breaker) to RPC, and used #8 for all machine feeds as they are long and can be extended to add machines. All machines have cord caps and receptacles. All larger machines have internal breakers to protect the machines. AC tends to be quite dirty and input voltage can vary thought the day. The Idler in our system is a Howell (very robust and heavy compared to other 7.5 3PH motors) continuous duty, RPM 1725, 21 amp @230 (lower as Idler) and SF of 1.15 . I have not experienced issues with this set up, even during the summer months when AC input is the dirtiest.
If you decide to mount your RPC, use vibration isolators to mount the Idler as this will prevent horrific harmonics, ask me how I know lol.
Thank you firestopper for that info. It seems that maybe I should go with a larger motor but, the 10 should work fine in my application; I hope. If not, I will cross that bridge. I should never be working the machine hard to have that high of a demand for power. I will let you all know how it turns out. Thank you very much for all of the input.
F
Firestopper
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Your welcome,
Is the VFD for your mill single phase input or 3 ph input?
Is the VFD for your mill single phase input or 3 ph input?
F
Firestopper
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We're on the same page. Single circuit for all equipment. VFD's are very nice to have on a mill/lathe.
Looking forward to your progress.
Looking forward to your progress.