New Motor Design
New Motor Design
(OP)
General Question from a mechanical engineer:
I have a motor that I have been using for many years and now is being discontined. I have a source in China that I sent the motor too to duplicate. Recieved the new one but it does not electrically function the same. One of the technicians sent them the following electrical data to duplicate:
Universal wound AC/DC
no load speed= 10,000 RPM
load speed= approx. 7400 RPM
load current at 7400 RPM= 6.5A
rated voltage= 230V
duty rating is intermittent
130C thermal rating.
Is this enough info. to design a motor? I don't think so.
What is critical for electrical design, rotor lock current?
I got back the following info from the supplier before he shipped us the prototypes:
Apparantly, my technician approved these values. Looks alot different to me although only a ME.
No load speed= 10,000-12,000 RPM
output power without load= 250W
load speed= 7400 RPM
load current at 7400= 1.5 A instead of 6.5A
output power with 7400 RPM= 180W
Here are some tested differences between old and new
old:
100% voltage (220V) 3.26 amps
100% voltage and no load: 1.51 amps
new:
100% voltage (220V) 2.41 amps
100% voltage and no load: 1.05 amps
Help please?
I have a motor that I have been using for many years and now is being discontined. I have a source in China that I sent the motor too to duplicate. Recieved the new one but it does not electrically function the same. One of the technicians sent them the following electrical data to duplicate:
Universal wound AC/DC
no load speed= 10,000 RPM
load speed= approx. 7400 RPM
load current at 7400 RPM= 6.5A
rated voltage= 230V
duty rating is intermittent
130C thermal rating.
Is this enough info. to design a motor? I don't think so.
What is critical for electrical design, rotor lock current?
I got back the following info from the supplier before he shipped us the prototypes:
Apparantly, my technician approved these values. Looks alot different to me although only a ME.
No load speed= 10,000-12,000 RPM
output power without load= 250W
load speed= 7400 RPM
load current at 7400= 1.5 A instead of 6.5A
output power with 7400 RPM= 180W
Here are some tested differences between old and new
old:
100% voltage (220V) 3.26 amps
100% voltage and no load: 1.51 amps
new:
100% voltage (220V) 2.41 amps
100% voltage and no load: 1.05 amps
Help please?





RE: New Motor Design
Is it possible that the new data are for continuous duty while the original data were for intermittent duty? What duty factor were you using the original motor in?
The tested curent consumption is also confusing. Is the new motor consuming 2.41 A when loaded while the old motor consumed 3.26 at the same load and speed? If that is the case, I would say you got yourself a much better motor now.
Do you have excessive arcing (more than before) with new new motor and at full load? If not, you can relax and feel very comfortable.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: New Motor Design
At a minimum, specify output torque at some speed and a certain duty cycle (be more specific than "intermittent"). You may also want to specify the maximum allowable temperature at certain points that can be measured in the armature, field and commutator. You may also want to specify the grade of the insulation and the hipot test it must pass.
Additionally you may want to specify maximum locked rotor torque and amps, how well it commutates, and maximum runout of the motor shaft.
RE: New Motor Design
How would I measure the output torque of the old motor, under its load?
RE: New Motor Design
You may need to cool the brake if running for an extended period. And you always have to be very careful so you do not hurt yourself or anyone else.
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: New Motor Design
Althogh the current does not necessarily follows a proportional rate to the power, 6.5 amps on the original motor are far appart from the 1.5 amps that the new motor will handle. Aparently the new motor has only 25% of the original power.
RE: New Motor Design
RE: New Motor Design
I have a table listing the amps, watts input, rpm, and torque oz. in and HP, watts out at 190V
Sample:
190 amps .90 watts(rdg.23) watts (corr.115) rpm 15350 torque 0
190 vac amps 3.52 watts 620 rpm 7000 torque 68ozin hp .47
this table covers about 9 lines with different current results.
RE: New Motor Design
Volts Amps In RPM Torque (oz/in) HP Watts Out Efficiency
190 0.9 MAX 0 0 0 0.0%
190 1.75 10000 20 0.1985 147.7 46.8%
190 2.78 8000 45 0.357 266 53.2%
190 3.52 7000 68 0.472 352 56.7%
190 4.35 6050 88 0.527 394 52.5%
190 4.45 6000 90 0.537 400 52.5%
190 5.35 5000 118 0.586 437 49.0%
190 6.25 4000 148 0.587 437 43.8%
RE: New Motor Design
CODE
In (oz/in) Out
190 0.9 MAX 0 0 0 0.0%
190 1.75 10000 20 0.1985 147.7 46.8%
190 2.78 8000 45 0.357 266 53.2%
190 3.52 7000 68 0.472 352 56.7%
190 4.35 6050 88 0.527 394 52.5%
190 4.45 6000 90 0.537 400 52.5%
190 5.35 5000 118 0.586 437 49.0%
190 6.25 4000 148 0.587 437 43.8%
RE: New Motor Design
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com