|
Title: Help in understanding brushed power systems Post by: AnjanBabu on October 10, 2013, 12:57:56 AM Recently, a friend offered me a HPI Thunderbolt 15T brushed motor and HPI SC-15WP ESC. Unfortunately, the ESC got fried up pretty good right after connecting it to the battery, reasons unknown. The motor however is in good shape.
I do not have an ESC right now and I'm looking to buy one if it's affordable. I looked up the specs for the HPI SC-15WP ESC and surprisingly, it's rated to 200A. I tried searching for 200A brushed ESCs and I couldn't figure out the brushed system terminologies all too well, all the ESCs are all rated in terms of motor turns. And I dont see the KV rating on most brushed motor specs, if any that I could find, it was specified in RPM calculated to the max voltage the motor can handle? Also, can a 540 sized 15T brushed motor candle anything close to 200A? considering a modest 100A @ 8.4V, it can deliver 840W! sounds like a lot of power for a motor that size? ??? Title: Re: Help in understanding brushed power systems Post by: AnjanBabu on October 11, 2013, 06:15:10 PM Bump.
Title: Re: Help in understanding brushed power systems Post by: 1firefly2 on November 25, 2013, 06:12:57 PM Dear Sir,
The following link will give you the rough idea about turn to K V rating: http://www.teamnovak.com/products/brushless/motor_spec_chart.htm You can order the same ESC from Tower Hobbies or other sites: http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXBSWP&P=0# Kindly note that these are the max ratings of ESC which it can tolerate for some time. Actual current draw is proportional to the load. Title: Re: Help in understanding brushed power systems Post by: iamahuman on November 25, 2013, 07:27:08 PM The 200A ratings are false.
Title: Re: Help in understanding brushed power systems Post by: rajathv8 on November 25, 2013, 07:52:00 PM Hey Anjan,
It may be worth trying to figure out what went wrong. Was the battery connected correctly? +ve to +ve? Also what type of battery did you use? What are you planning to use this setup on? It may pull a lot of current when you blimp the throttle but not sure if it would reach 200A. Some companies make standard ESCs which they use over a range of cars and trucks - HPI probably used 200A although this setup may not draw such numbers. Lower the number of turns, more power the motor delivers, more current it draws. So you need an ESC which can handle a 15 turn motor. Did you look at this (http://www.hobbyking.com/hobbyking/store/__32025__hobbyking_x_car_45a_brushed_car_esc.html) ? Title: Re: Help in understanding brushed power systems Post by: AnjanBabu on November 25, 2013, 08:25:38 PM Not sure what happened to the ESC, it was from a HPI Savage kit, I tihink. The terminals were soldered right and I connected it to a 2S LiPo as suggested for the ESC and tried to caliberate it, but it only got hot. The second time, even the battery got really hot. On the third attempt, a plume of white smoke. The motor was going on and off randomly all that while.
I'm planning to use the motor in a boat right now, I'm sure the motor won't draw anything beyond 50A continuously. Surprisingly, no one has attempted to measure how much current it draws or hasn't posted online. I can't even seem to find out the typical power rating of a 15T capable ESC. I got the same HobbyKing x-car 45A a few weeks ago,use it for a a week and I fried that to, white smoke all over again. This time in a cheap toy car!! Brushed systems are being a pain. I'll have to replace a few MOSFETS to try and make it work. Otherwise I'll just have to throw in a couple of STDP switches and a servo to control it the motor. |