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Loosing the perm motors for some less powerful units, space is limited bosch 750s are just too big too fit, any ideas on small yet Powerful motors, some mag motors look good including the short can motors as used in big nippers claw etc but might be too small as drive motors as advised by the big nipper boys, any other options previus experineces with these style of motors etc , thanks for reading and replys
ceros will be back soon
There are the iskra 800w motors
Those ain't smaller than a Bosch 750.
Also, length seems to be the problem, not the diameter.
No, not a lot of options to replace a Perm. Maybe that the Ampflow A28-400 can fill in the gap.
The A28-150 ain't up the task, unless geared very high, delivering a slow machine.
I am looking to relocate the motors lenght not some much of a problem but width looking around 130mm long less then 100mm high
looking at f30-150 ampflow motors possibly,good power for size
Even lower power than the A28-150's. And those ain't recommended for a heavyweigt drivetrain.
Why do you want less powerful units? If the current motors already fit, and are too powerful, then why not just limit their output?
PJ's got a point, it's easy enough to set dual rates on a TX so it's not running full capacity.
Plus if you run Batteries at double the desired voltage and have half throws on your Tx you don't suffer from any voltage drop, makes for a much more agile robot.
I agree with all the above, but I current limited my roboteq to 80amp per channel and running at 6s in the first fight the esc cut out due to overheating and in the second fight just let go. Space is very tight in ceros and any changes is a nightmare. but I don't see any other options maybe in a different machine with less traction the perms would be great but in the confined space and lipo batts the roboteq is just not upto the job, hoping to speak to Ian Watts about a mega wotty if that will handle the powerbut I don't have the cash for a new unit without selling other parts?.
I will repair the roboteq again in due time then send it out for testing in someones donar machine, but the same thing will happen again without motor or design changes
Which Roboteq have you got? If you've got the standard can you get it upgraded to the HE one.
Can you heatsink Roboteq more to keep it cool.
From memory the perms were a pain to drive, I know they melted Dogs Bollox's controllers in seconds.
ax2550 I think 120 amp per channel, it was not hot when it went bang which I though was strange,
You said in the 1st fight it cut out, I was just guessing it might be the thermal trip cutting in.
Might be worth seeing you can get the speedo upgraded to the HE version as its 140amp, think it got double the number of FETS to (someone who knows roboteqs better will know). We looked at both the HE and Mega Wotty to run Mutes Lems on, we went for the Mega Wotty because it fitted better.
We stick the speedo directly to Mutes chasis and us the whole robot as a heat sink and we've never had it cut out
The perms are the problem, they generate huge spikes in current and voltage (back emf). I don't even think a megawotty will handle them. As lots of people found out years ago when speedos just went up in smoke!
Happy to replace them, or try a new esc but the option needs to be right as I can't afford another blowup at least for a while anyway, still like the mini Macs, at 2.3hp look good but Mario doesn't agree anymore takers
I wouldn't use the 150 sized Mags, the 400s would be best.
2.3Hp =1700W=70 amps on the F30-150.
The heavier, fan-cooled Bosch 750gpa is rated at 40 amps.
Nominal torque @1700W for the F30-150=2.3 Nm.
Bosch 750 does 2.2Nm , but at half the RPM of the F30-150
In short. I'm not convinced the F30-150 is a suitable heavyweight drive motor.
I won't stop you from trying , and will eagerly look to the results. Getting small motors 1.8 kg less than the old style Bosches ain't something to sneeze at.
But gear down a lot... That's my advice.
Get a set of 800w iskras. Got a bunch here that were used in typhoon2. Same diameter as the magmotor just longer. Sealed as well. Nice motors.
Iskra sound ok what are the dimensions
2 seconds. I'll go measure
80mm diameter (give or take) and 150mm without shaft, 170mm shaft included.
These are rough measurements. I have had a bottle of wine this evening so they are plus or minus 5mm
too long I only haver 170mm max and must include all gearbox stages and mountings etc, its a tight space
Sounds a bit too tight. I'd modify the chassis
wish I could but the main chassis brace and cross brace sit on that bulkhead, along with the arm lower stop and when the arm shuts it sits 60mm inside the chassis as it has a ladder style brace construction in titanium so even if I removed the bulkhead the arm would then foul the motor. its a nightmare only the small mag motors would fit upto know with a small single stage box and a pinion output to the kart wheels
Motor in wheel sounds like the only viable option.
Change the wheels. Typhoon 2 used wheels that were two inches wide
there is one last drastic option which means removing the custom buffer tank and installing the motors at the rear of the machine, this then allows the fitment of bosch motors or mags in the rear but leaves no space for a off the shelf buffer tank. the weight is then no longer centred over the wheels and the new buffer would be small, also I would need to move the esc but to were I don't think it will fit anywhere else
Just playing devil's advocate, is there any viability to the cost of experimenting with some big brushless motors? It feels a bit soon tech-wise but in theory it should be possible? You'd want lots of reduction and a bit of slop in the transmission so the motors have the best conditions for starting up, but, certainly the power ratings are easily there in the brushless world. There are several large car ESCs that can be programmed to optimise them for robot drive use. In a heavy I don't think you'd notice any delay, as most feather and raptor size machines now running brushless drives are getting perfectly usable control.
It may simply be too soon/too much of a fuss with all that's involved, but if you intend to rebuild the transmission then the potential of experimentation is opened up. Again just putting the thought on the table.
If I remember right the wheels on Ceros are smooth and wide. As Gary says, they could be a lot smaller, giving you not only way more internal space, but less strain on the motors as less rubber has to be shoved around when turning.
Another option could be change your wheels to something smaller in diameter and use the empty space above to mount some different motors? Yes it does mean a bit of messing around but it should open up your options more and still keeps the weight over the wheels
Could you use a 90 degree gearbox?
Or rewind your perm motors with more/less windings (can't remember which) to decrease the number of amps drawn/power?
Or maybe use an electronic solution to reduce current eg. Massive resistor, or a large capasitor to reduce current spikes?
anyone got dimensions for the bosch 400w gpa motor as they might be small enough to shoe horn into the front as the 750s are just a little to large
Fairly sure they are the same size as the 750. If not exactly the same they are very close in size.
They use the same can-with different vent holes- and magnets, but the rotor is different. Outside dimensions are the same.
boo that's annoying the perms might have to stay in and just get a mega wotty to handle them, ceros is all in bits and im struggling to find and answer for the motor dilemma at the moment, bosch 750s and e30 400s will fit if I remove the buffer tank major mod to the internal braces and cut out the roboteq mount
Ceros back to bare bones, ampflow e30-400 is my top runner due to size power and price, anyone running this motor along with mega mouse
Storm 2 uses 'm to now.
Pretty sure Storms running the A28-400s
E30-400 it is looking at 12:1 two stage gearbox 1st stage mod2 technobots gears, any advice for output shaft diameter and what bearings have been used in the past ie, kronic, manta, eruption all have similar drive setups this design works well so why reinvent the wheel looking to just remod this design suit my purpose, help and advice welcome cad drawings welcome
I apologise for jumping into an old thread. I am also building a robot using a Roboteq AX2550 and 2 Magmotors (S28-400) for the drive. I was worried by the problems that Ceros had had. Could you tell me how you finally resolved the issue? I wondered whether the answer might be to reduce the maximum current per channel to 60 amps, or put fuses in the motors feeds - perhaps at 80 amps or perhaps 120 amps to protect both the controller and the motors. The Roboteq manual talks about 'flyback', caused by the motor impedance which means that the current to the motor can be significantly higher than the current from the battery. How do other roboteers get around this problem?