Timeline for DC brushed motor - smooth ramp-up to max power
Current License: CC BY-SA 4.0
15 events
| when toggle format | what | by | license | comment | |
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| Jun 10 at 12:54 | comment | added | winny | If not a full-on MOSFET drive for it, how about a smaller relay in series with some parallel 12 V light bulbs or <1 ohm resistor for the first 130 ms? Regarding diodes, if you add some series resistance, you can parallel several regular silicon. | |
| Jun 10 at 12:42 | history | edited | winny | CC BY-SA 4.0 |
kelvinwatt, kelvinampere -> kilo
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| Jun 10 at 5:35 | answer | added | Autistic | timeline score: 0 | |
| Jun 9 at 19:59 | history | edited | Andrius Narbutas | CC BY-SA 4.0 |
added 142 characters in body
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| Jun 9 at 19:44 | comment | added | Andrius Narbutas | About diodes - if i need diode to handle all motor current/voltage spikes - then it's "huge thing" (closest available diode which can handle 300A/120V is > 100A and weights 280g alone). Do all high-current brushed setups use such diodes? | |
| Jun 9 at 19:38 | comment | added | Andrius Narbutas | Wires from batteries to contactor are 7-20cm long (battery connectors over range 7...20cm), from contactor to motor ~40cm, AWG8 everywhere. I connected cheap scope to contactor, so ~40cm from motor wires. My question is not "why controller died", more about "what methods i should use", but i also posted model in comment above (pwrcontroller.com/product/crocodile-hl50200-dc-motor-controller if i remember correctly). And about last question - cost/setup and availability issue (to explain in details this will take way more space than original question) | |
| Jun 9 at 15:21 | comment | added | TimWescott | Please edit your question with more detail. Lead lengths matter -- far more so on the battery than the motor side. Give a dimensioned sketch of the battery hookup, or, if the wires show, a photo with a ruler for scale. Tell us where in the circuit you're seeing 120V spikes. Post the PWM rate of the controllers you tried. If your commercial motor controller has a datasheet, post it. Explain why you're trying to achieve 3kW with low voltage and high current, instead of using more cells in series and fewer parallel stages. | |
| Jun 9 at 5:33 | comment | added | greybeard | Are there capacitors between neighbouring commutator segments and/or brush holders? | |
| Jun 9 at 5:32 | comment | added | greybeard |
have good working (mechanically) solution a pity, rather - if it was lacking, it would be easier to seek a solution storing&absorbing mechanical energy.
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| Jun 8 at 23:42 | comment | added | user319836 | Understand the difference between "free-wheeling" voltage also known as back-emf due to rotation of the armature and "inductive-reaction" voltage due to \$di_L/dt\$. The latter is the reason for the diode across the motor. It must be able to handle the maximum motor current. | |
| Jun 8 at 22:02 | comment | added | Kevin White | You will certainly need diodes when using a PWM controller (they may be included on the controller itself). You will also need to be extremely careful with inductance in the motor leads as that can cause large voltage spikes. That controller has a large amount of decoupling capacitance so inductance in the power leads should not be a problem. | |
| Jun 8 at 19:36 | comment | added | Andrius Narbutas | Currently i do not have diodes (because i'm using contactor and LiPos are absorbing freewheeling power). When used custom built mosfet controller (just on/off) i used many TVS diodes (12x3KW if i remember correctly), did not prevent mosfets from burning. About commercial controller - IIRC it was HL50200. | |
| Jun 8 at 19:31 | comment | added | Kevin White | Did you have diodes across the motor? What commercial controller did you try? | |
| S Jun 8 at 19:11 | review | First questions | |||
| Jun 8 at 20:48 | |||||
| S Jun 8 at 19:11 | history | asked | Andrius Narbutas | CC BY-SA 4.0 |