Save my EPmag!!

[Hgblues]

what is the negative effects of having the dwell too low? Mine for instance, at 7, versus the possibly recommended 15.

[smeek]

what is the negative effects of having the dwell too low? Mine for instance, at 7, versus the possibly recommended 15.

I'm no expert but I'll throw in my 2 cents here.

Too short of a dwell will either not fire or it will let the sear return before the bolt does which can cause resetting issues as was mentioned earlier in the thread. I'd assume this causes more wear on parts as well.

I wouldn't really compare timmy and mag dwell times, timmy's are moving more mass with the low pressure side a further distance than mags are. With a mag I'd just make the dwell long enough to keep the sear out of the way, since it won't affect velocity like a low dwell on a timmy will.

[athomas]

Yes, a dwell that is too low will cause wear and possible bolt stick issues. The original emags used a dwell of about 30ms for reliability. We have found through experimentation and measuring the bolt cycle time, that you can use a 15ms dwell quite reliably with a level 10 bolt system. If the dwell is too low, it could slow the bolt cycle time due to friction. When this happens, there is less available time to recharge the chamber. If the next shot is fired before the chamber is fully charged, you could experience a "chuff" and/or shoot down.

Most sear trippers, even low pressure solenoid controlled air piston types always use the same amount of air regardless of dwell time. The air doesn't pass through the system, it just pushes against the piston. They are constant volume so the volume always remains the same unless there is a leak in the air system. The one place these air systems can save air is if their internal volume is decreased. If they operated at a higher pressure or if the air lines are longer or if the qevs or fittings hold more air, then the air usage will be greater.

[Spider-TW]

With a mag I'd just make the dwell long enough to keep the sear out of the way, since it won't affect velocity like a low dwell on a timmy will.

That's the best part of an EP mag; once the sear clears the bolt, you can just about forget about it. Solenoid on-time just needs to be short enough to allow for the rate of fire when you include the recharge time.

You can't directly compare e-mag solenoid dwells either. But what you do see in all of these systems is the relative coil duty cycle and minimum time it takes to actuate the mechanical side of the device. 6 to 7 ms appears to be the common minimum time to either start a larger solenoid or open a pilot valve and start loading a cylinder.

E-mag and timmy systems have some mechanical inertia that you can use. This is very visible when you go to a light ram in a timmy and have to turn the dwell up. MPA-3s don't have much to offer for mass. You just have to fill the ram with air at enough pressure to push the sear, pretty much pound for pound.

The main point is that you don't want to set the on-time of your solenoid exactly at the point where your LPR can supply the exact amount of air because you are dealing with flow, pressure, and volume when you do that. Stuff that air in there and let it work so that you really just need good supply pressure. That's an advantage of EP mags and it's why I play with my EP mag over my timmy until I hit a field with an air station a quarter of a mile away from base.

[p8ntbal4me]

What I always do is start with what the defaults that are from the board you are using to do the work. Because the UTB has no way of telling you what its current setting are, you should go back and reset the board once you are at the point of playing with the settings.

Look here: Ripper frame powered by a UTB

The settings used in that frame are as follows:

SETUP 1
ROF = 18
Dwell = 15ms
Debounce =
Eye Delay = 15ms
Eye Type = Break
Force Semi = 2 sec

SETUP 2
Shot Q'ing = On
ABS = 0ms
After Nitro = Semi
Trigger Speed = 5bps
Trigger Pulls to Ramp = 4 pulls
Training = Off
Training Dwell = 10ms
Auto-Off = Off
Instant On = Off

SETUP 3 = Not used

SETUP 4 = Not used

I did change a few settings to tweek it to go really fast,.. but that dwell listed is what produced an nice shot rate and full cycles.

~ P8nt

[p8ntbal4me]

what is the negative effects of having the dwell too low? Mine for instance, at 7, versus the possibly recommended 15.

Remember,.. the longer the solenoid stays "open" or "on" means more air going to the ram to push the sear.

If you have a dwell that is too low,.. you don't have enough air behind the ram to push the sear fully to the rear,.. which is (IMHO) no different than short stroking the trigger with a manual frame.

~ P8nt

[Hgblues]

Yea, I can see that now P8nt. After seeing that and Spider's post, with my dwell at 7 I'm probably seeing that very scenario, where after ripping a quick string, the ram's not catching the sear with enough force, causing what I'm seeing as a "chuff", but is actually the EP version of a short stroke.

Now, I have several variables here that I believe need minor adjustment, however, I don't want to change to much at one time, so that I know I'm going the right way with the adjustments. The level X seems to be fine, and I don't believe needs to be addressed at this time. Basically I'm looking at the dwell adjustment, which I'm going to bump to 15, and the ULT change. However, with the conversations going on, I'm thinking the dwell adjustment is going to make the biggest difference.

Knowing what we're looking at now, what's your opinions on the ULT now? Definitely change the ULT out? or it maybe a non factor here?

[p8ntbal4me]

Yea, I can see that now P8nt. After seeing that and Spider's post, with my dwell at 7 I'm probably seeing that very scenario, where after ripping a quick string, the ram's not catching the sear with enough force, causing what I'm seeing as a "chuff", but is actually the EP version of a short stroke.

Now, I have several variables here that I believe need minor adjustment, however, I don't want to change to much at one time, so that I know I'm going the right way with the adjustments. The level X seems to be fine, and I don't believe needs to be addressed at this time. Basically I'm looking at the dwell adjustment, which I'm going to bump to 15, and the ULT change. However, with the conversations going on, I'm thinking the dwell adjustment is going to make the biggest difference.

Knowing what we're looking at now, what's your opinions on the ULT now? Definitely change the ULT out? or it maybe a non factor here?

Alright,.. let me say this about the level x:

In that video that I linked you to,.. that valve has a level x installed.... as you can see it works just fine :)

As for the ULT,... I have had better results with the stock on/off installed over the ULT. So my suggestion is to tune the valve without the ULT and with the stock On/Off installed without the electronic frame mounted,...

At that point, you have eliminated one problem already.

The EP setup can fire quickly,.. and I feel you need an On/Off pin that will assist the ram in resetting as quickly as you can afford to get it to. If you want "real world as we know it" comparisons,... its like using a ULT in an E-Mag,... not recommended for sear reset reasons. The EP isnt much different.

~ P8nt

[Hgblues]

ahh, I gotcha. That clears up my ULT questions. I got the ULT with the gun brand new, which is why it's in there now. I have the stock one also, however, so I'll change that out. Gonna see if I can get by my local field (DSG, owned by a huge mag fan) tomorrow and try these changes out. I'll post up my results as soon as I get a chance to test.

[Spider-TW]

I'm with P8nt on the RT on/off over the ULT. I tried the ULT and it was a very sticky and the lower pressure was not working well on my LPR. However, I have been told by several serious pneu users that they like ULTs.

I am pretty sure that if you use a ULT in a pneu, you need to tune it as if you were going to use it normally, which means shimming it to the point of full auto and backing down.

[p8ntbal4me]

I have been told by several serious pneu users that they like ULTs.

Yup,.. in a Pneumag setup,.. ULTs can be good,.. but you dont really need it unless you want to allow the least amount of air and force to the valve that you possibly need.

When talking about Hyperframes and Devil Mags,.. you NEED a ULT because the stroke length of the solenoid is so short and fine,... using a stock on/off just doesnt cut it as far as reliability and battery life.

~ P8nt

[Hgblues]

I haven't left you guys hangin' with my project. Just ran into a bit of a snag. Got ready to go test the new settings at the field this past weekend, only to realize I can't get into the settings mode with my UTB. The eye's button on my membrane pad doesn't do anything, so I'm not sure I have it hooked up correctly to where the board recognizes that button. I'll update when I get a chance to see how I wired it up. It's been a while.