methods
1 GW
Hello,
This post is borderline Marketplace but before we talk about sales I would like to talk about field testing.
We have in our possession a handful of modified 75-5 and 75-7 motors that have been paired with a Sevcon Gen 4 and a custom crimped wiring harness.
View attachment 5
Some motors have a complete carbon wrap and some are a hybrid of steel band and carbon wrap. We have a screening process that runs the motors up to a fixed RPM while monitoring temperature and power. To pass, this particular batch of motors have run for 20 minutes at 5500 RPM with temps hitting 110C to 120C. This is as much confidence as we can build in the lab so we would like to put 10 out in the wild to get some validation data.
I have been avoiding unnecessary destructive testing... but some of the tests have been up to 6,200 RPM for extended periods at high temp. The relationship between force on the carbon wrap and RPM can be described by this formula:
RCF (or G-force) = 1.12 x R x (RPM/1000)²
Note that there is a squaring of RPM so that should tell you that the difference between 5000RPM and 6000RPM can be considerable. Below is some data based on the above formula.
If these calculations are correct (somebody peer check please) then that tells us that to run at 6000RPM instead of 5000RPM we experience a 50% increase in force!!! That's considerable... and plays heavily into our methodology for assessing margin and reliability. Its not possible or representative to just "over-test" the motors to some arbitrarily high RPM as it will result in D-Test (Destruction). Instead reliability is assessed by burning in at a margin RPM for a period of time that allows thermal equilibrium to be achieved.
All that is great - I trust the data.
Thats how we do it with a lot of aerospace stuff that we cant just launch into space willy-nilly....
Whats better is FIELD DATA....
oooooooohhhhhh....
Something we rarely got to work with at the National Lab.
So... We are looking for some candidates who want to act on an opportunity to get some very nice motors paired to some very nice controllers with a custom firmware flash and (Not to Exceed XYZ) engineering support from yours truly.
This isn't a blowout sale so please be ready to pay market on the parts. This is a value-add run where we are offering to get your project up and running (don't underestimate the difficulties...) in return for some basic run-time data. We are interested in the following applications:
* Marine applications - sail boats, out-runner conversions, custom rigs (but beware the corrosion!)
* Road applications - Tadpoles, light EV's, solar cars, student projects, karts, you name it
* Air applications - Anything that can glide
* Generation applications - Wind mills, hydro electric, regenerative, etc.
* Nerd applications - Hey... if you want to just tinker with the system and report back that's fine too.
Lets let this be an open space to speak of the technical ins and outs of what the motors are capable of, what applications are appropriate, etc.
On site here we have a Dyno that should be capable of up to 50hp. We are testing at 24V, 48V, and >96V. Current levels from 10A to >400A
If you are interested start sounding off in this thread and lets talk about how we can get the ball rolling with some really interesting projects. If you have any data on your load profile we can start by running those numbers here to get an idea of how good the match is.
* Continuous and peak RPM
* Torque/Thrust
* Load profile (load vs time)
* Cooling availability (thermal mass, airflow, liquid)
* Available Power (48V, 96V...), chemistry (lead or lithium), capacity etc (so we can profile in sag under load, max current, continuous current, run time,...)
-methods
This post is borderline Marketplace but before we talk about sales I would like to talk about field testing.
We have in our possession a handful of modified 75-5 and 75-7 motors that have been paired with a Sevcon Gen 4 and a custom crimped wiring harness.
View attachment 5
Some motors have a complete carbon wrap and some are a hybrid of steel band and carbon wrap. We have a screening process that runs the motors up to a fixed RPM while monitoring temperature and power. To pass, this particular batch of motors have run for 20 minutes at 5500 RPM with temps hitting 110C to 120C. This is as much confidence as we can build in the lab so we would like to put 10 out in the wild to get some validation data.
I have been avoiding unnecessary destructive testing... but some of the tests have been up to 6,200 RPM for extended periods at high temp. The relationship between force on the carbon wrap and RPM can be described by this formula:
RCF (or G-force) = 1.12 x R x (RPM/1000)²
Note that there is a squaring of RPM so that should tell you that the difference between 5000RPM and 6000RPM can be considerable. Below is some data based on the above formula.
If these calculations are correct (somebody peer check please) then that tells us that to run at 6000RPM instead of 5000RPM we experience a 50% increase in force!!! That's considerable... and plays heavily into our methodology for assessing margin and reliability. Its not possible or representative to just "over-test" the motors to some arbitrarily high RPM as it will result in D-Test (Destruction). Instead reliability is assessed by burning in at a margin RPM for a period of time that allows thermal equilibrium to be achieved.
All that is great - I trust the data.
Thats how we do it with a lot of aerospace stuff that we cant just launch into space willy-nilly....Whats better is FIELD DATA....
oooooooohhhhhh....
Something we rarely got to work with at the National Lab.
So... We are looking for some candidates who want to act on an opportunity to get some very nice motors paired to some very nice controllers with a custom firmware flash and (Not to Exceed XYZ) engineering support from yours truly.
This isn't a blowout sale so please be ready to pay market on the parts. This is a value-add run where we are offering to get your project up and running (don't underestimate the difficulties...) in return for some basic run-time data. We are interested in the following applications:
* Marine applications - sail boats, out-runner conversions, custom rigs (but beware the corrosion!)
* Road applications - Tadpoles, light EV's, solar cars, student projects, karts, you name it
* Air applications - Anything that can glide
* Generation applications - Wind mills, hydro electric, regenerative, etc.
* Nerd applications - Hey... if you want to just tinker with the system and report back that's fine too.
Lets let this be an open space to speak of the technical ins and outs of what the motors are capable of, what applications are appropriate, etc.
On site here we have a Dyno that should be capable of up to 50hp. We are testing at 24V, 48V, and >96V. Current levels from 10A to >400A
If you are interested start sounding off in this thread and lets talk about how we can get the ball rolling with some really interesting projects. If you have any data on your load profile we can start by running those numbers here to get an idea of how good the match is.
* Continuous and peak RPM
* Torque/Thrust
* Load profile (load vs time)
* Cooling availability (thermal mass, airflow, liquid)
* Available Power (48V, 96V...), chemistry (lead or lithium), capacity etc (so we can profile in sag under load, max current, continuous current, run time,...)
-methods
