View Full Version : stumped


dertsap
02-18-2006, 06:05 PM
i just got some vexta nema34 ph299-02 motors they are 2 phase 6v 2amp 1.8 degree ,
, i was running vexta ph268e 1.5 nema23 motors that were 5.4v at 1.5 amp .9 degree
my power supply has more than enough amperage to run these motors but for some reason the new ones only run at half the speed compared to the old ones , i bought these new ones because i need more torque and i thought that if they were near the same voltage they would run as fast
are nema 32 slower than the nema 23 normally or what
ive configured my software to the diffenent steps/in , , the only possible thing that i can see is that i am a little over sized on my resistors , so the motors are only getting 1.8 amp / phase , i know i need to change them but isn t it rule of thumb that voltage = speed , amperage= torque , if so than i don t understand why the are so slow

ger21
02-18-2006, 07:20 PM
If you look at torque curves, you'll see that generally the larger size motors lose torque faster as rpm's increase, so larger motors usually don't spin as fast.

They shouldn't spin only half as fast, though. What drives and what voltage are you using?

dertsap
02-19-2006, 12:25 AM
im using the fet3 at 28v ,
i got two pairs on ebay i just tryed the other pair they are the ph 299-01 3v at 4 amp , unfreaking beleavable the difference , configured using mach 2 controller these things are rotating unmounted at over 160 in/min , i still haven t pushed it till it started loosing steps yet ,this one is doing some serious rpm , what a difference ,ive got to take a second look at the other motor i must have connected wrong or something , but judging by the torque on the one running right now i have no doubt that i will be safely running at 70 - 80 in/min ,

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