Way too much heat!

[Si Coe]

Well after the problems with my LRP Sphere / LRP X11 7.5 combo it was suggested I try another motor, so I acquired a Novak 4.5R. Now I know its a 'hot' motor, but I didn't expect what happened.
First test run (D4, stock spur, 18 pinion on tarmac) it ran for about 3 minutes, before one of the battery leads came desoldered. It had near totally drained a 4300 Lipo in that time, and the Deans connector had melted!

So thinking I'd got the gearing wildly wrong, I switched to the smallest pinion I own, a 15, soldered on a new deans plug, put a different pack in and tried again. This time I managed about 30 seconds before a wire came unsoldered. The Deans connector had melted again.

By now I'm getting concerned, so after replacing connectors (again) I tried gently revving the car on its stand. As you nail the throttle you can feel the wires getting warmer. Even off the ground, the heat is immense. However the drivetrain itself rolls nice and freely.

All the wires involved are 14awg Novak, the connectors proper Deans. The ESC gets hot, but doesn't thermal. The motor is very warm, but not scorching.

I assume something is badly wrong here, but what bit is at fault?

[shanks]

Black to black - Red to red

[DCM]

4.5 + 4wd buggy is not a good idea, it is more a TC morot.

Also, the ESC settings are probably far too wrong for that motor.

[Si Coe]

I wanted to see if the ESC was working after earlier problems, so I used what I had. In any case a 4wd buggy on tarmac with the shell off isn't really any harder on the motor than a touring car.

But you might be right about the settings being wrong - the brakes seem awful sharp.

[shanks]

Si

Check your battery connections = if you have 4mm plugs into the battery they can get loose and dirty and as resistance equals heat...........

MattB had a similar problem with his - new 4mm plugs and a clean out of the battery sockets (think he used nail varish remover on a cotton bud) and job sorted...

[westie]

Maybe something shorting on the motor connections or even on the carbon?

[DCM]

Originally Posted by Si Coe

I wanted to see if the ESC was working after earlier problems, so I used what I had. In any case a 4wd buggy on tarmac with the shell off isn't really any harder on the motor than a touring car.

But you might be right about the settings being wrong - the brakes seem awful sharp.

no, the loading on the motor from the transmission is a lot more, bigger wheels to rotate for starters, plus a buggy weighs more too.

But, as long as the motor is ok, I would look at the settings, timing advance and throttle limiter for starters.

[ashleyb4]

Check your solder joints on your speedo and check all your connectiong in my opinion sounds like a dry joint.

A

[Si Coe]

OK, well......

Set the punch, brakes etc to minimum. Manual doesn't mention timing advance.

Put the car on the stand, then temp gun in hand gentle rev the motor. After about 10-20 seconds at 1/3rd throttle, motor is at 28C, ESC is reading 41.8C and the wire joining the two halves of the saddle is at 48.2C. Then the capacitor exploded in a shower of sparks. I switched off immediately

So I'm guess that due to the fact the motor never even got warm the problem isn't there. I guess its the ESC, hence the capacitor blowing. I take it a faulty capacitor alone wouldn't cause these problems?
In which case who fixes LRPs (its second hand so no warranty) and what sort of price are we talking? This foray into sensored motors is proving expensive and fruitless so far.

[ashleyb4]

Glyn Ward is the man you want to talk to about LRP repairs. Im sure someone will come along with his details.

A

[bigred5765]

sphere or sphere tc,?? sphere has a lower limit than a 4.5

[DCM]

The capacitor could of been at fault, email SMD for tech support.

[Si Coe]

Its a Sphere TC. Well at least thats what I was told it was - I bought it off Kopite. It doesn't have any stickers on it though so I'm only going on his word. It does have the heatsink and the fan, and certainly looks like a Sphere TC!

Is it worth replacing the capacitor and trying again. I can easily source a replacement capacitor and fit it, but I'm concerned repeated attempts to isolate the fault might just damage more things!

[NeilD]

Originally Posted by Si Coe

Its a Sphere TC. Well at least thats what I was told it was - I bought it off Kopite. It doesn't have any stickers on it though so I'm only going on his word. It does have the heatsink and the fan, and certainly looks like a Sphere TC!

Is it worth replacing the capacitor and trying again. I can easily source a replacement capacitor and fit it, but I'm concerned repeated attempts to isolate the fault might just damage more things!

Contact Jamie at SMD.

[Rich D]

I have Pm`d you Derek Baileys details - hes the man

[NeilD]

Originally Posted by Rich D

I have Pm`d you Derek Baileys details - hes the man

No Rich you're da man!!!

[ashleyb4]

Yea if kopite says its a TC its a TC he is a trust worth guy.

A

[Si Coe]

I'm sure he is trustworthy. Its just with no stickers I can't confirm or deny!

[Si Coe]

Thank you everyone.

I've emailed SMD tech support to hear their verdict, and kept Derek Baileys details to send to for repairs. I think I've sent him stuff in the past (like 10+ years ago!) and he was very good.
In fact I might send a bust servo along as well.......

Hopefully I can get it all up and running soon. For the few minutes it ran it was pretty mental fast with that motor!

[NeilD]

Keep us all updated, dude.