Striatech DVR motor for PM's 2-3 HP lathes 1236,1236T,1340GT.. etc

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skcncx

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Anyone consider a Striatech DVR motor for a variable speed lathe motor conversion?

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They call it a "Switched Reluctance Motor", it seems their motor type is unique. I have one on my Nova Drill press and Rikon Band saw... great for dialing in the right speed and making my band saw go from 100 SFPM for steel, all the way to 1500+ SFPM for wood. I was as in my local hardware store and noticed they were selling the 1.75 HP at a pretty good discount and thought it seems like a decent option for the 1236T lathe I plan to buy.

They tout:
- max torque over the entire speed range
- smarts to keep desired RPM constant based on monitoring load (as well as saving power consumption when load is lower)
- and many other things.

They show torque and RPM curves for the 1HP motor... did not find them for the larger motors.

I'm also not sure how much external input signaling you can wire (if any) to these like you can a VFD. For instance, on the 1236T, I would need to send input from the motor control lever on the apron to signal you want to start the lathe and which direction depending on up or down you are moving the lever.
 

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matthewsx said:
$800 to $1000

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striatech.com striatech.com
Click to expand...
Yea. Not cheap. Not sure how this compares to a VFD and motor combo though.

I picked up the 1.75 HP one for $600.

I'm going to research this a bit more and reach out to them... if I can start/stop, change direction, wire in e-stop from external controls, even possibly have my own RPM dial... seems like that's all I would need to seamlessly incorporate into the PM-1236T.
 
Not a lot of information as to the dimensions and performance characteristics of the Striatech reluctance motors. The main selling point seems to be synchronous speed, more compact size and efficiency; but not much different than a BLDC motor or encoder based (software or mechanical) feedback VFD inverter motor. A VFD with an inverter/vector motor in SLV mode will have a speed regulation of better than 0.1% and will maintain constant torque typically down to 6 Hz with an inverter rated motor. Vector motors will be down to almost 0 speed and can develop 200% of rated torque or higher out to the rated base speed for up to a minute. I did not see any information as to the base speed of the reluctance motor but a torque chart showed that it was not much different than a non-synchronous inverter motor. Running a non-synchronous inverter motor above its based speed you gain the mechanical advantage to Hp/Torque for the rated RPM. So the reluctance motor may be a consideration if replacing a single phase motor, and needing a smaller motor frame, but unfortunately there is no information as to the Striatech controller, programming, external inputs, etc. and also braking ability/use of an external braking resistor. The last aspect of not being able to control the braking rate and lack of external controls would be a concern in this application in my view.
 
mksj said:
Not a lot of information as to the dimensions and performance characteristics of the Striatech reluctance motors. The main selling point seems to be synchronous speed, more compact size and efficiency; but not much different than a BLDC motor or encoder based (software or mechanical) feedback VFD inverter motor. A VFD with an inverter/vector motor in SLV mode will have a speed regulation of better than 0.1% and will maintain constant torque typically down to 6 Hz with an inverter rated motor. Vector motors will be down to almost 0 speed and can develop 200% of rated torque or higher out to the rated base speed for up to a minute. I did not see any information as to the base speed of the reluctance motor but a torque chart showed that it was not much different than a non-synchronous inverter motor. Running a non-synchronous inverter motor above its based speed you gain the mechanical advantage to Hp/Torque for the rated RPM. So the reluctance motor may be a consideration if replacing a single phase motor, and needing a smaller motor frame, but unfortunately there is no information as to the Striatech controller, programming, external inputs, etc. and also braking ability/use of an external braking resistor. The last aspect of not being able to control the braking rate and lack of external controls would be a concern in this application in my view.
Click to expand...
Thanks for the input. I have very little knowledge of VFD and all the types of motors... seems you really gotta know what you are ordering to ensure your motor is of the right type, paired with a right sized and featured VFD etc. A bit daunting for the uninitiated. It's not even like you can buy VFD & motor combo kits... or I'm looking in all the wrong places.

I'll see what striatech tells me, but if you cannot control this thing with external inputs, it's not really an option. For a tool that could just use their control panel, seems like an easy, all in on solution. That's why it looked attractive to me. Initially, I plan to order the PM-1236-T single phase.. and if the RPM range via the gear box suffices, I'll just save my money.

On the striatech you can control the braking rate and ramp up time in their interface on the controller they give you.... as to how robust it is and how much force it can take to brake would be a question I have. A small thing, but if it's as efficient as they say, saving amp draw and power is a small benefit.
 
Read Mark's threads and posts and you'll learn an awful lot. A good VFD can do a whole lot and integrate with the whole machine.

John
 
I have to say I'm a bit underwhelmed by the Striatech specifications. But really no more expensive than a standard 3 phase motor and VFD combination. The only advantage I can see is the slight power savings. The torque curve is really nowhere near as good as a standard 3 phase motor and a sensorless vector VFD, which is normally pretty flat from about 3 Hz to 60 Hz at 100% torque, and then falls off as the speed increases above 60 Hz.

The real downside I can see is control limitations and the lack of a suitable interface.
 
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Striatech called me back. It's as expected, no interface to externally control their motor. However, they are working on it for their future controller. With some custom mods, they may have something I can do now but they have to talk to their engineers before getting back to me again.

While I'm going with the single phase on the PM-1236T to start I still plan to keep my eyes open for an "easy" way to put a variable speed motor on it. Ha, easy.... after hours of research and lots of questions :). Everything is easy... once you understand it and have done it once.

Seems like with all the variable speed motors out there, why not do away with the gear box, just a low/high pulley set and do the rest from a motor that has torque through the range... out of the box of course :).

Based on RPM calculators, turning 1" aluminum stock, I should be around 500 SFM which calculates out to 1900 RPM, double that for .5" stock. The PM-1236T only goes to 1800. Though, on my atlas 618, I max out at 1500 RPM and can get a decent finish... so, for the newbie, it's hard to know where to start. Seems like most lathes top out around 2000 RPM. Do people actually turn at 2000-4000 rpm?

My brain is just hurting from trying to nail down what lathe, motor combo, electronics if I go the VFD route eventually, DRO choices, so many particulars.
 
Still need gears for torque multiplication.

If it was me ordering a new lathe I’d go with 3 phase even if I just used a static converter to start.
 
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