Team Losi RX-280 replacement option?

NeoNot · Nov 02, 2009, 11:15 AM

I am hoping for a little help from the aerial guys.
I have been looking for a replacement motor for the Team Losi RX-280 motor, used in the Mini-T, Mini Late Model, Slider, Desert Truck, etc......

Over the last two weeks I have searched the web for numerous options that appeared to be options for me only to find that the items are either no longer made or not availible here in the states.

What I know about the RX-280 motor.

I have completely disassembled one of my motors and here is the specs that I have found on the motor.

19-20 turn (depends on how you count the windings)
.50 mm wire used in windings.
Approximate RPM 25000-35000 no load.
Front and rear bal bearings.
External brushes.

Unknown items.

Watts
Torque
Amp draw

I could figure out the Watts and amp draw if I still had a stock motor. I have mod'd all mine so I am not sure what the stock items would be.

Anyways I am looking to replace these motors with a cheaper alternative or a better quality motor that will last longer. Presently these motors cost me around $14-15 and I am replacing them on a 2-3 week basis. We race the stock class so I must keep the motor that same size, 280, but I am allowed to use any motor that out there except those marked Modified, aka the Reedy motor.

I have seen the Electric Fly 280 BB at Tower and some Perplex, as well as a few others but can not seem to locate these motors from a US online store, nor can I find out the specs on a lot of these motors!

I need to replace the stock motor with one that can handle a 5 minute run time on a 2S 20C lipo. The motor will most likely be getting max current for roughly the full 5 minutes of run time! The stock motor can only handle this for about 2-3 weeks before it is cooked and doesnt preform at peak level which results in a much slower car!!!

If possible I would like to keep the cost of the motor at the price of the $14-15 or less but if a good quality alternative is availible at a higher price and it will last I am not beyond purchasing it either.

In case you are wondering why I am posting this in the airplane forum, all my searching has pointed towards these types of motors being used in the hobby flight more than the hobby ground vehicles.

Any and all help is greatly appreciated!!!

vintage1 · Nov 02, 2009, 12:21 PM

that's probably a sagami made 280 hot motor like the permax 280BB.

If you are cooking it, best to go up to something bigger. losi 400, permax 400 BB or a cobalt 400.

Oh. you are not allowed to replace.

Hmm. I think you are stuck then.

NeoNot · Nov 02, 2009, 10:58 PM

Is there any option for rewinding the motor with a different configuration?

Say a 19/20x2 or anything along these lines that may help?

I mod'd a couple of the motors for this evenings race. One of them I turned into a 17 turn motor and the other one I turned into a 13x2 turn motor. With the higher rpms the motor actually seemed to run cooler but I was having issues keeping the windings attached to the commuter <sp???

Anyone have any suggestions on how to attach the windings to the to com other than a solder connection?

By the way if you guys want any pics of the motor let me know. I have about 11 of them laying here in different stages of tear down.

vintage1 · Nov 03, 2009, 05:35 AM

Probably optimum power for a shortish race with good cooling will come at 30K RPM or so in a motor like that. The more RPM ,the more power, until typically you run into brush burn and brush bounce. So a thicker wire higher KV wind may well help. As will fan cooling.

The word you are looking for is commutator

If you are melting the solder off that, its getting pretty hot..

NeoNot · Nov 03, 2009, 07:54 AM

I wasnt melting the solder off the commutator. It was getting spun off. I wasnt able to get a real good connection joint made to the tab and wire. All the heat from the iron was going to the wire so it got most of the solder with only minor flow to the tab on the commutator.

Presently the brushes come out of the motor with a copper tint to them. They appear to be a graphite grey color before running the motor. The wear of the brush actually looks good. It is a nice smooth wear pattern with no pits or chunks missing.

As far as fan cooling goes that is already happening. The biggest problem is getting a decent amount of air flow with the fan. Due to how the motor is mounted you are limited to a 25x25x10mm fan and needless to say these fans dont move that much air!!! I have been thinking about a peltier cooler but from what I have read it appears the size I would have to make that cooler wont allow me to mount it to the motor.

Can you recommend a site/sites to find the wire for rewinding the motor?
Can you recommend a site/sites that offer the sagami or other motors that may match the losi preformance?

vintage1 · Nov 03, 2009, 08:04 AM

Quote:

Originally Posted by NeoNot

I wasnt melting the solder off the commutator. It was getting spun off. I wasnt able to get a real good connection joint made to the tab and wire. All the heat from the iron was going to the wire so it got most of the solder with only minor flow to the tab on the commutator.

Bigger iron needed then.

Once rewound, you should possible epoxy the wires in place near the commutator.

Quote:

Presently the brushes come out of the motor with a copper tint to them. They appear to be a graphite grey color before running the motor. The wear of the brush actually looks good. It is a nice smooth wear pattern with no pits or chunks missing.

As far as fan cooling goes that is already happening. The biggest problem is getting a decent amount of air flow with the fan. Due to how the motor is mounted you are limited to a 25x25x10mm fan and needless to say these fans dont move that much air!!! I have been thinking about a peltier cooler but from what I have read it appears the size I would have to make that cooler wont allow me to mount it to the motor.

then probably you cant do much more there. The answer is to get the best out of what you have.

Quote:

Can you recommend a site/sites to find the wire for rewinding the motor?

Not in the USA, no. Plenty of links from this forum.

Quote:

Can you recommend a site/sites that offer the sagami or other motors that may match the losi preformance?

I don't think that will help. You are constrained really by the magnets, the size, and the actual motor type. If you are allowed, you might re-magnet with neodymium. Otherwise its down to matching the motor to the pack by accurate rewinding, and adjusting the gear ratios to suit, and maybe a bit of quality bearings replacement, and commutator polishing, plus tweaking the advance a bit.

Pre cooling the motor with dry ice before a race might net you a bit as well.

NeoNot · Nov 03, 2009, 08:26 AM

Is there a thread that maybe helpful to find the needed supplies for rewinding a motor?
I am not sure what to search for so I used motor winding supplies. This search returned no useful links.

vintage1 · Nov 04, 2009, 04:54 AM

any of the motor kit suppliers will have suitable wire. Juts google enammelled copper wire.

A good start is to unwind a ruined motor and put a micrometer on the wire, work out its gauge, and test wind with a gauge bigger, seeing how many turns you get on, then try that on all three phases and run it, and see where you get.

NeoNot · Nov 04, 2009, 10:04 AM

Is there a certain type of epoxy that is recommended for sealing the joints to the com?
How much larger in diameter would you go with the wire?
After doing some measuring and calculating it appears the current wire is a 24 gauge. .188 mm is the area of the wire and according to the various charts I have found this puts it closest to 24 gauge. I was thinking about moving up to 22 or 21 gauge but wasnt quite sure how much higher to go.

After doing some testing with the motors I rewound, before they came apart, I found that a 13x2 produced about the same preformance as a 12x1 winding. Is there going to be any more or less current draw or heat with one of these options?

I never got a full five minutes out of either motor but I did get around 3.5-4 minutes of run time on them before they came apart. I think the biggest issue I had was how the wires were mounted/soldered to the com. I had the cut the old windings so I could do each leg of the armature seperate. When I reattached the wires I soldered the wire to the top of the com instead of pulling up the solder tab and placing it below the tab like it was originally. On top of that the way the motor was rotating put all the stress on the solder joint until it pulled the com apart, at the solder joint.

I have already aquired another handful of bad motors from the race Monday night so I should have plently to play with until I can get this right.

Other than the big dollar remagnitizing machines is there another mean to realign/magnitize the magnets in these motors? On all of them that I have taken apart to date, none of them have any problems in the windings it is simply a much lower magnetic field.

I have proved this theroy to myself by taking a new motor and swapping the armature from it to an old motor and it preformed the same as the old armature. When I swapped the old armature into the can it preformed the same as the new can and new armature.

From the various reading I have done it sounds as though the heat causes the magnets to lose their polarity/alignment which results in a weaker magnetic field. By placing the magnets inside of a electro magnetic coil you can realign them and regain the biggest majority of the magnetism they originally had.

This may all be a waste of time if sourcing magnets would be cheaper than trying to remagnitze them.

Sorry for the long post. Just trying to wrap my head around this process and soak up some info so I am better prepared for the task at hand.

NeoNot · Nov 07, 2009, 08:25 PM

Anyone else have any more thoughts???

Fourdan · Nov 10, 2009, 05:24 PM

Hi Neo
Look here for a Mini-T with a brushless
http://christopheb34.free.fr/Mini%20..._brushless.htm
Try to translate from french to english via Babelfish or any translator
Louis

NeoNot · Nov 20, 2009, 07:37 PM

Sorry for the delay in my response.

I appreciate the link but I am not looking for a brushless system. I am trying to find a more reliable brushed motor that is in the 280 class, like the stock Losi RX-280 motor.

From everything I have been able to determine the airplane motors seem to be what I need to look at but I have not been able to locate any vendors for these types of motors other than the ElectricFly motor sold by TowerHobbies.

If anyone has any links to vendors that sale these types of motors with the external brushes, bearings and not bushings in a 280 case I would love to look at them to see if they would be a worth while replacement for the stock motor.

I am not beyond spending more money for a different motor if it is better quality and will last me more than a month.

I have three of these motors that I have to replacement almost monthly and I want either a cheaper alternative or a better quality motor but it must be no bigger than the stock 280 motor or I cant compete in the same class that I am currently in.

vintage1 · Today, 04:48 AM

Ah. Now I had thought that in fact the LOSI was a Sagami motor, as the only LOSI I have is a raced tuned Sagami..400 sized. But it is in fact simply the old Mabuchi.

What you want is the Permax 280BB. But very few people sell them.

http://www.mhm-modellbau.de/part-332538.php

Kyosho also rebadged the Sagami IIRC.. Looks like the 28BB may suit.
.
From exporience, if the KV is the same you get about 10% more power and 30% less heat out of a sagami. MUCH better magnets.

Nov 02, 2009, 11:15 AM	#1
NeoNot Registered User Join Date: Nov 2009 Posts: 8	Team Losi RX-280 replacement option? I am hoping for a little help from the aerial guys. I have been looking for a replacement motor for the Team Losi RX-280 motor, used in the Mini-T, Mini Late Model, Slider, Desert Truck, etc...... Over the last two weeks I have searched the web for numerous options that appeared to be options for me only to find that the items are either no longer made or not availible here in the states. What I know about the RX-280 motor. I have completely disassembled one of my motors and here is the specs that I have found on the motor. 19-20 turn (depends on how you count the windings) .50 mm wire used in windings. Approximate RPM 25000-35000 no load. Front and rear bal bearings. External brushes. Unknown items. Watts Torque Amp draw I could figure out the Watts and amp draw if I still had a stock motor. I have mod'd all mine so I am not sure what the stock items would be. Anyways I am looking to replace these motors with a cheaper alternative or a better quality motor that will last longer. Presently these motors cost me around $14-15 and I am replacing them on a 2-3 week basis. We race the stock class so I must keep the motor that same size, 280, but I am allowed to use any motor that out there except those marked Modified, aka the Reedy motor. I have seen the Electric Fly 280 BB at Tower and some Perplex, as well as a few others but can not seem to locate these motors from a US online store, nor can I find out the specs on a lot of these motors! I need to replace the stock motor with one that can handle a 5 minute run time on a 2S 20C lipo. The motor will most likely be getting max current for roughly the full 5 minutes of run time! The stock motor can only handle this for about 2-3 weeks before it is cooked and doesnt preform at peak level which results in a much slower car!!! If possible I would like to keep the cost of the motor at the price of the $14-15 or less but if a good quality alternative is availible at a higher price and it will last I am not beyond purchasing it either. In case you are wondering why I am posting this in the airplane forum, all my searching has pointed towards these types of motors being used in the hobby flight more than the hobby ground vehicles. Any and all help is greatly appreciated!!!

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Nov 02, 2009, 12:21 PM	#2
vintage1 Replikit Designer Join Date: Sep 2002 Location: East Anglia, UK Posts: 27,378	that's probably a sagami made 280 hot motor like the permax 280BB. If you are cooking it, best to go up to something bigger. losi 400, permax 400 BB or a cobalt 400. Oh. you are not allowed to replace. Hmm. I think you are stuck then.

Nov 02, 2009, 10:58 PM	#3
NeoNot Registered User Join Date: Nov 2009 Posts: 8	Is there any option for rewinding the motor with a different configuration? Say a 19/20x2 or anything along these lines that may help? I mod'd a couple of the motors for this evenings race. One of them I turned into a 17 turn motor and the other one I turned into a 13x2 turn motor. With the higher rpms the motor actually seemed to run cooler but I was having issues keeping the windings attached to the commuter <sp??? Anyone have any suggestions on how to attach the windings to the to com other than a solder connection? By the way if you guys want any pics of the motor let me know. I have about 11 of them laying here in different stages of tear down.

Nov 03, 2009, 05:35 AM	#4
vintage1 Replikit Designer Join Date: Sep 2002 Location: East Anglia, UK Posts: 27,378	Probably optimum power for a shortish race with good cooling will come at 30K RPM or so in a motor like that. The more RPM ,the more power, until typically you run into brush burn and brush bounce. So a thicker wire higher KV wind may well help. As will fan cooling. The word you are looking for is commutator If you are melting the solder off that, its getting pretty hot..

Nov 03, 2009, 07:54 AM	#5
NeoNot Registered User Join Date: Nov 2009 Posts: 8	I wasnt melting the solder off the commutator. It was getting spun off. I wasnt able to get a real good connection joint made to the tab and wire. All the heat from the iron was going to the wire so it got most of the solder with only minor flow to the tab on the commutator. Presently the brushes come out of the motor with a copper tint to them. They appear to be a graphite grey color before running the motor. The wear of the brush actually looks good. It is a nice smooth wear pattern with no pits or chunks missing. As far as fan cooling goes that is already happening. The biggest problem is getting a decent amount of air flow with the fan. Due to how the motor is mounted you are limited to a 25x25x10mm fan and needless to say these fans dont move that much air!!! I have been thinking about a peltier cooler but from what I have read it appears the size I would have to make that cooler wont allow me to mount it to the motor. Can you recommend a site/sites to find the wire for rewinding the motor? Can you recommend a site/sites that offer the sagami or other motors that may match the losi preformance?

Nov 03, 2009, 08:26 AM	#7
NeoNot Registered User Join Date: Nov 2009 Posts: 8	Is there a thread that maybe helpful to find the needed supplies for rewinding a motor? I am not sure what to search for so I used motor winding supplies. This search returned no useful links.

Nov 04, 2009, 04:54 AM	#8
vintage1 Replikit Designer Join Date: Sep 2002 Location: East Anglia, UK Posts: 27,378	any of the motor kit suppliers will have suitable wire. Juts google enammelled copper wire. A good start is to unwind a ruined motor and put a micrometer on the wire, work out its gauge, and test wind with a gauge bigger, seeing how many turns you get on, then try that on all three phases and run it, and see where you get.

Nov 04, 2009, 10:04 AM	#9
NeoNot Registered User Join Date: Nov 2009 Posts: 8	Is there a certain type of epoxy that is recommended for sealing the joints to the com? How much larger in diameter would you go with the wire? After doing some measuring and calculating it appears the current wire is a 24 gauge. .188 mm is the area of the wire and according to the various charts I have found this puts it closest to 24 gauge. I was thinking about moving up to 22 or 21 gauge but wasnt quite sure how much higher to go. After doing some testing with the motors I rewound, before they came apart, I found that a 13x2 produced about the same preformance as a 12x1 winding. Is there going to be any more or less current draw or heat with one of these options? I never got a full five minutes out of either motor but I did get around 3.5-4 minutes of run time on them before they came apart. I think the biggest issue I had was how the wires were mounted/soldered to the com. I had the cut the old windings so I could do each leg of the armature seperate. When I reattached the wires I soldered the wire to the top of the com instead of pulling up the solder tab and placing it below the tab like it was originally. On top of that the way the motor was rotating put all the stress on the solder joint until it pulled the com apart, at the solder joint. I have already aquired another handful of bad motors from the race Monday night so I should have plently to play with until I can get this right. Other than the big dollar remagnitizing machines is there another mean to realign/magnitize the magnets in these motors? On all of them that I have taken apart to date, none of them have any problems in the windings it is simply a much lower magnetic field. I have proved this theroy to myself by taking a new motor and swapping the armature from it to an old motor and it preformed the same as the old armature. When I swapped the old armature into the can it preformed the same as the new can and new armature. From the various reading I have done it sounds as though the heat causes the magnets to lose their polarity/alignment which results in a weaker magnetic field. By placing the magnets inside of a electro magnetic coil you can realign them and regain the biggest majority of the magnetism they originally had. This may all be a waste of time if sourcing magnets would be cheaper than trying to remagnitze them. Sorry for the long post. Just trying to wrap my head around this process and soak up some info so I am better prepared for the task at hand.

Nov 07, 2009, 08:25 PM	#10
NeoNot Registered User Join Date: Nov 2009 Posts: 8	Anyone else have any more thoughts???

Nov 10, 2009, 05:24 PM	#11
Fourdan Registered User Join Date: Sep 2003 Location: Antony (France) Posts: 1,507	Hi Neo Look here for a Mini-T with a brushless http://christopheb34.free.fr/Mini%20..._brushless.htm Try to translate from french to english via Babelfish or any translator Louis

Nov 20, 2009, 07:37 PM	#12
NeoNot Registered User Join Date: Nov 2009 Posts: 8	Sorry for the delay in my response. I appreciate the link but I am not looking for a brushless system. I am trying to find a more reliable brushed motor that is in the 280 class, like the stock Losi RX-280 motor. From everything I have been able to determine the airplane motors seem to be what I need to look at but I have not been able to locate any vendors for these types of motors other than the ElectricFly motor sold by TowerHobbies. If anyone has any links to vendors that sale these types of motors with the external brushes, bearings and not bushings in a 280 case I would love to look at them to see if they would be a worth while replacement for the stock motor. I am not beyond spending more money for a different motor if it is better quality and will last me more than a month. I have three of these motors that I have to replacement almost monthly and I want either a cheaper alternative or a better quality motor but it must be no bigger than the stock 280 motor or I cant compete in the same class that I am currently in.

Today, 04:48 AM	#13
vintage1 Replikit Designer Join Date: Sep 2002 Location: East Anglia, UK Posts: 27,378	Ah. Now I had thought that in fact the LOSI was a Sagami motor, as the only LOSI I have is a raced tuned Sagami..400 sized. But it is in fact simply the old Mabuchi. What you want is the Permax 280BB. But very few people sell them. http://www.mhm-modellbau.de/part-332538.php Kyosho also rebadged the Sagami IIRC.. Looks like the 28BB may suit. . From exporience, if the KV is the same you get about 10% more power and 30% less heat out of a sagami. MUCH better magnets.