Ev Warrior Re-timing

 

This modification will let you set the timing of an EV Warrior to neutral, CCW, CW or really advanced for one direction applications.(spinners)  It is accomplished by attaching the existing brush plate to the rear motor housing and removing the mounting tabs that hold it in place. Read the whole set of instructions first!  I describe how I did the modification but I also have some other suggestions that might be better for your application.  This is by no means the only way to do this but it is relatively easy and works well.  If you figure out a better way to do this feel free to post your ideas on the forum.  I'd be interested to see what else people come up with.

 

 Tools Required

A Hammer.

A punch w/a flat round head ~1/4"

A center punch

A small wire brush

A dremel with a cutting wheel.  (a slim grinding wheel would be ok )

A Drill press (or hand drill is ok ) and A round "rat tail" file

A regular flat blade screwdriver

A pair of pliers preferably needle nose

A Pair of  6" wire cutters ( this is what I used but the size isn't critical )

A dial caliper for measuring spacer thickness to .17"

A high wattage 150+ soldering iron (I used an old 200/275w iron but the tip was at less than stellar)

 

  Parts

(2) 10-32 Allen head bolts (again personal preference but you could use screws or hex head bolts) + washers and nuts.

 In the photos you will see my first unit I modified where I used three. 2 blots are enough.

(2) 10-32 Threaded aluminum spacers modifiable to .17" thickness.  The ideal part here would be threaded Teflon spacers. You could possibly use a nut and stacked washers to get close enough thickness. The spacers need to keep the bolt captive.

(1) .1ufd capacitor.(noise suppression not required but highly recommended.)

(2) brass 8-32 machine screws nuts and washers.

 

Step 1.Score a reference mark  for a reference alignment between the main can and the back plate of the motor. This will be your timing reference.  Remove the back of the motor by using a medium flat blade screwdriver to pry the tabs that hold the rear of the unit on.  Don't pry them any more than you have to.  They won't break but you don't want to stress them any more than necessary.

 

 Step 2. With the back off the motor notice where the brushes ride on the commutator.  You will ultimately want to recreate this level. Find a spacer to hold the brushes in place because you will need to remove the brush holder next and  THEY ARE SPRING LOADED!!!!!!!  Usually a pop bottle top works.  I used The little case Bird watt meter slugs come in.  It's 1 5/32nds across and worked really well.  You will notice 2 round holes in the brush housing these are going to be the holes you will use. One of them has some plastic fins around it.  You will need to remove these. (pic 1)

 Ev mod 1 cut tabs here.JPG (65137 bytes)

Step 3 (pic 2) The blue arrow shows where the "grounding tab" is that needs to be removed.  If you are using the aluminum spacers like I did you will need to trim some of the brass traces away.  If you going to try and use a nut and washers you will need to trim accordingly.  However if you manage to scrounge up some Teflon you can skip the brass trimming part where the red arrows are. You will still need to remove the grounding tab.

 Ev mods 2 Trim here.JPG (66300 bytes)

IMPORTANT!!!!----->  You need to trim the ribbing (the raised plastic ridges) from around the holes so the spacer sits flat against the brush housing.  If you don't do this the spacers will hold the brushes too far down the commutator and could wear the brushes out quickly and/or the  motor won't run well.  Take you time here.

 

F.Y.I.   Brushes "break in or wear in" to the commutator similar to the way the pads on a cars brakes do.  As the commutator rubs on the brushes they form the groves and wear to the angle of the commutator as a "custom fit" if you will.  So the closer you keep the brush plate to it's original orientation the less re-breaking time and wear the brushes will suffer because of this little mod.

 

Step 4. Take the back of the case and pound the ridges out in the areas marked on photo 3.  Make sure you don't bend the case.   For minimum case distortion use a hammer and a flat nosed punch on a hard flat surface. An anvil would be the ideal here but smooth concrete will work I used a flat edge on my vice.  Now place the flat side of the brush housing w/the traces on the back housing.  The connector should line up against the s/n# stamped in the rear housing.  The ribs you just flattened should align under the holes. If they don't check to make sure the connector is sitting in it's proper ridge.

 Ev mods 3 Smash and drill here.JPG (60008 bytes)

IMPORTANT!!!----> To properly center the brush housing to the back of the motor align the three outer tabs on the brush housing so they match up to the edge of the three tabs on the back of the motor that held it in place.  There should be ~ equal spacing all the way around the edge of the brush housing relative to the outer flange of the rear housing. (this does assume that there was no significant damage to the motor to begin with and minimal distortion during the flattening of the ribs but the tab alignment is what really matters)  Once you have it aligned use the center punch and make your mark for the holes.  If the case is in good shape the punch should mark on the center of the ribs that you flattened.  One will be near  a  point on  a rib you just flattened for the outside hole and one near  a "T" on the other flattened rib for the inside hole.  Now go use a 13/64ths bit and make you holes.

 

IMPORTANT!!!---->  Spacers.  This is the part that goes between the brush plate and the back of the housing. This is the part that will set the depth of your brushes on the commutator.  If you use ( what ever you use Teflon spacers, nuts and washers, calibrated widgets, petrified bubblegum etc) the tapped spacers like I did the total height of the spacer needs to be .17 inches (do use the calipers here).  It also needs to hold the bolt captive in the brush housing. I took 1/4" threaded aluminum spacers and ground them down.

 

Step 5 Now, go stuff a washer on the bolt and run it through the brush plate hole.  Use the threaded spacer or nut to hold it in place and repeat for the other hole. Now check the mount holes you just drilled. The bolts should slide pretty much straight in. It might be a tight fit, which is good because it maintains the position of the brush plate. What you donít want is the bolts being forced at an angle through the holes. The object here is to keep the brush plate from bending at all if possible.  If you have to force the blots through the hole The brush plate is what will flex.  If it flexes The brush alignment changes and you don't want that.   Use the round file to ream the hole a bit if you have to.

  At this point if you boogered the holes up really bad you can either ream the holes out really big and hope for the best or take out the bolts and spacers and put the whole mess back together and you've lost nothing except some time.

 

POINT OF NO RETURN.

Step 6 (pic 4,6) Now it is time to remove the tabs that held the brush plate in place. There are 6 of them. 3 on the brush plate and 3 on the rear housing.  When you remove the tabs on the brush plate you want to make it consistently round so it can rotate freely inside the can.  The tabs on the rear plate need to be removed so they can rotate freely inside the can also.  Otherwise they hang up inside the original tab indents in the can.

 Ev mods 4 remove tabs.JPG (66992 bytes)   Ev mods  6 tabs removed.JPG (65315 bytes)

Step 7 (pic 5) These holes Will allow you to inspect the actual Brush seating. It's not mandatory but It will give you an idea of the condition of the brushes.  I used a 1/4" drill and I'm planning on getting some spring caps to go over the holes.

 Ev mods 5 Drill inspection holes.JPG (67733 bytes)

OPTIONS for power terminals

 This is where we are going to modify the back of the motor and run the wire mount screws through.  You may want to do this a different way. Because the actual neutral rotation is only about 10 deg ( a little goes a long ways here and can be very touchy) or about 3/8 to 1/4' worth of actual travel I would consider keeping the original connector and cutting the can to accommodate it's rotation. (The reason I cut off the connector in this project is my mount uses the hole left by the connector as a "keyway" to keep it from rotating in the mount.  By doing this It will require less pressure on the case to keep it from rotating and there by giving it less chance of bending or distorting the case.)  I opted for the mechanical stability of actual bolts. Some people have soldered their wires directly to the traces. The most important thing to remember when soldering here is to clean the traces and bolts and use a good high power soldering iron.  If you neglect either of these you will get a cold joint and you connection will fail.

 Ev mods 7 Drill and solder screws.JPG (65373 bytes)

Step 8 (pic 8) Use a dremel with a cutting wheel to remove the wedge with the s/n on the back plate.  Drill a hole in the wide traces for the 8-32 screws to mount to.  Use a wire brush  and clean the traces, bolts and nuts. Slide the screw through the hole from the inside of the brush plate and secure it with a nut.  Now solder this assembly in place.  Repeat for the next trace. You may need to trim some of the hard ware with the dremel for clearance purposes.  I had to grind down a nut on one side.  This is also a good time to mount the .1uf rf noise suppression cap. Now reassemble the whole mess but don't lock down the tabs yet.  Look through the brush inspection holes. The brushes should be riding just below the edge of the commutator. Then look through the hole left by the power connector.  the brushes should be ~ 3/32nds above the bottom of the commutator. The plastic cover you see in the picture is actually Teflon. It came from a cooking store as a cutting surface.  It was flexible and about 1/16" thick A.K.A bot parts! Pc perf board or fiberglass would work well here also. What ever you use should be heat resistant and an electrical insulator. Secure the motor and put power to it.  There should be minimal sparks off the brushes.  If you see some it's ok this is normal in a brushed motor.  If you radically advance the motor you will see bigger sparks and the motor will get quite warm very quickly.  Also keep in mind that big sparks create more radio interference.

Ev mods 8 Trim and cap.JPG (54258 bytes) 

Step 9 Setting the timing to neutral.  You should now be able to twist the back plate brush assembly against the can. It's not going too rotate freely so you may have to separate the back from the can just a bit to adjust the timing. Start In the original timing position using the timing mark you made in the beginning (the score on the edge of the can and back plate). If using a ccw motor with the back plate facing you rotate the back plate clock wise. A CW motor will go rotate clockwise. If this is confusing think of it this way.  To advance the timing you turn the brushes the same direction as the shaft rotation.  To retard the timing you rotate the brush orientation opposite of the shaft rotation. The goal is to have the same speed in both directions.  Neutral timing is a compromise. When neutralized It will be turning slower than it used to in its original timed direction but it will turn faster in the opposite direction of which it was originally timed. 

 

 So how do I know when it's neutral?  Here are a few things to try.

1. Get an rpm meter like they use for model aircraft.

2. Poor manís (sneaky bastards) rpm meter.  Find an old hobby motor (don't use high end r/c car motors as they are usually advanced timed in one direction and will produce an asymmetrical voltage reading when reversed) and if you can direct couple the two shafts together (Can you say duct tape?  Very good.).   The next best thing to try would be a rubber wheel of some sort on the shafts and do a friction coupling.  The problem w/ this is slippage and the loss of accuracy that will occur. Hook the hobby motor to a volt meter and power up the EV.  When the voltage reading is the same in both directions you're done lock the tabs down.

3. If you have a power supply with an amp meter look for a null in the current draw as you change the timing.  The null is not quite neutral but it's pretty close.

4 Just listen.  The pitch of the motor as it rotates should be the same in both directions.

 

Re timing from CW to CCW  Seeing how there is a glut of CW motors and not so many CCW we'll do it this way. Take a current and rpm measurement of the CW motor or the motor you want to match.  In it's stock off the shelf configuration. After the modification with the back plate facing you rotate the back plate  clockwise past neutral to obtain the same reading in the opposite direction. As you do this you should be able to watch the current go down as it gets to neutral and start to rise again as it goes to advanced in the new direction.  The current is important because there is a curve where efficiency current vs. rpm starts to fall. Once you go past neutral the rpm and current go exponentially.  It can be a very touchy setting. I highly recommend a power supply with a current meter.

 

So there ya go.  Good luck  Rob Purdy (Team Gausswave)