(2) HV4.5 motors 1 is considerably slower. Worn out rotor? - RC-Monster Forums

Gee · 03:45 AM

I got the same setups (HV4.5) in two different RCs. My recently finished evo was notacibly slower then the emaxx. I swapped the esc and motor and now the evo is the faster. THe RC are setup the same 72/14 with the emaxx trannies locked in second and running (2) 2s2p. It has to be the one motor. It came with an esc off ebay. The two esc were both replaced with remanufactured ones with in the last two months and the other hv 4.5 motor was bought new september. I replaced the bearing in the older motor last month while I was waiting on the esc. Should I have replaced the rotor also? Anything else in a brushless motor that could cause a performance issue?

glassdoctor · 01.17.2008, 11:32 AM

Sounds like a weak rotor. The slower motor probably gets hotter too right?

I would pick up a new rotor for sure... sintered if you can.

Serum · 01.17.2008, 01:30 PM

Is it possible that one is using a sintered rotor and the other is not?

Gee · 01.17.2008, 03:43 PM

When I replaced the bearings in the motor the rotor looked like the picture of the sintered rotor that's on tower. What would an older one or not sintered rotor look like?

Serum · 02:55 AM

an awful lot like the sintered.

there are a few differences though, i looked it up on the internet some time ago, and there was a thread on another forum i can't recall, but they had pictures of both rotors.

Gee · 01.17.2008, 06:38 PM

Thanks. I was looking up prices for the sintered rotor and found for only another 8.00 or so I could get the motor replaced with a remanufactured one. Not knowing for sure if it is a rotor problem. That may be the best route to take. I got a 6.5 I can use until I get the other one back. Besides the bearings and rotor is there anything else too a brushless motor that is servicable?

NovakTwo · 01.17.2008, 06:59 PM

Quote:

Originally Posted by Gee

Thanks. I was looking up prices for the sintered rotor and found for only another 8.00 or so I could get the motor replaced with a remanufactured one. Not knowing for sure if it is a rotor problem. That may be the best route to take. I got a 6.5 I can use until I get the other one back. Besides the bearings and rotor is there anything else too a brushless motor that is servicable?

That sounds like the best plan. The rmf replacement motors have a new 120 day warranty.

Serum · 01.18.2008, 02:56 AM

A sintered rotor for 8 bucks? that sounds like a 2nd hand to me? What you can do first is swap the rotor from the powerful motor to the less powerful one and see if that 'solves' the problem.

suicideneil · 01.18.2008, 07:03 PM

Well, I was playing with my motor last night- had to re-tap the front mounting plate since most of the holes where clogged with... crap. Here are a couple photos of the old rotor:

Front

Back

The newer sintered rotors have a shinyer finish, and the thin metal 'jacket' around the magnet overlaps the edges, right upto the rotor shaft almost- the old jacket clearly doesnt, and just wraps around the diameter of the magnet.

You can compare your magnets/rotors just by removing the front endbell- no need to pull out the rotor since its a nightmare to get back in....

lincpimp · 01.18.2008, 07:27 PM

Looking at the motor, I find the humor of novak having issues with a 5mm shaft. Why not leave the shaft the original size and not turn it down to 1/8. That way the shaft would be stronger and people would stop saying that it will not work in a new emaxx.

suicideneil · 01.18.2008, 07:54 PM

I had the same thought a long time ago- it clearly is a 5mm shaft that has been turned down to 1/8", but I didnt realise the signifigance until I joined up to this forum and learned of motors with 5mm shafts. Its scary how much I have learnt from RCM, and even scarier is how weak this old rotor is- the new one is such a great improvement, tons of bottom end torque from it.

Gee · 01.18.2008, 08:12 PM

Quote:

Originally Posted by Serum

A sintered rotor for 8 bucks? that sounds like a 2nd hand to me? What you can do first is swap the rotor from the powerful motor to the less powerful one and see if that 'solves' the problem.

I meant for 8.00 more than what the rotor would cost me. I could get the remanufactured motor. Sintered rotors go for around 34.00 (39.00 from Novak) and a remanufactured motor from Novak would be 42.00. Swapping rotors is a good idea.

Thanks for the pictures neil. Looking at those picture, the motor in question does have a sintered rotor in it. It has the jacket that over laps the end as you said.

suicideneil · 01.18.2008, 08:25 PM

My work here is done...

Still strange though, but I can only imagine that the system from ebay had been overheated, which killed the magnet. Re-manufactured escs means they are both 'new', as is one of the motors, but you are then left with the one dud motor, or rotor atleast. Thats my theory; get the remanufactured motor, then everything will be 'new', and hunky-dorey hopefully.