Spikes with Motors
 

Does anyone know if a spike can be used to run a johnson motor on last years controller (2003)? The manual does not really state that it can't, but does not say that it can.

Thanks.

-Greg The Great

I don't think the Johnson Motor was in the kit last year, but according to the rules from 2002, the Johnson can be run from a relay module. It hink the reason the rules exclude it this past year is because the motor wasn't in the kit.

So the spike would need to be fun to a relay instead of a PWM?

Can anyone confirm this for me?

Thanks,

-Greg The Great

The spikes do in fact connect to the relay connectors on the IFI controller. I'm not sure exactly what would happen if you connected it to a pwm, but as they use the same voltage range, it would probably work anyway (but not suggested). The difference is the PWM's can output a range of values, the relays only puts out of and on.

Would it be able to jun a Johnson 12 volt DC motor, on a Relay Out?

-Greg The Great

Yes, connect the motor to the spike and run the spike off of one of the relays.

based on your previous posts, you (Greg) don't have a lot of electronics experience, so don't try this!

The signals are not compatible, and definetly won't work.

I hope everyone understands that the power for the motor and relay comes from the fuse panel, not the robot controller. It is only the signal (forward, reverse, or off) that comes through the small three-wire cable from the controller.

You should be able to control a spike thru the pwm output. You would have to set the values to either 0, 127, or 254 for reverse, neutral, and forward respectively. If the signal is close to 0, 127, or 254, the spike should turn on, but I dont think it will work with any other value.

That will not work. The signals are not compatible. The connectors are the same but you cannot interchange PWM's and Relay Outputs. Please do not do that.

Matt

Thats What I was thinking...

However a Johnson can go on a spike and then to a Relay Output correct?

Thanks for The Help All,

-Greg The Great

Greg, I suggest you ask one of the other members or mentors on your team before you try any of this. As we cannot really see how you have hooked it up before you apply power we cannot really tell you if somthings going wrong, if you read the manuals to the control system located here
quick start guide

http://www.innovationfirst.com/FIRST...tart_Guide.pdf

http://www.innovationfirst.com/FIRST...ence_Guide.pdf

those should get you pretty well started

I am aware on how to set up the main system, what I am asking is if a SPIKE (this years (2k3)) can operate a motor, I know how the connections go, and all that stuff, I just do not know if a spike can run a Johnson 12 Volt DC motor. The manual says (selonoids, pumps, etc.) Does this include motors, I am aware of how to connect it and how to run it to the breaker pannel and all that fun stuff, I just do not know if a spike can run a motor. Does anyone know if it can???

Thanks,

-Greg The Great

I know the spike can do light, compressor window, seat, and the tiny little Johnson if that is the one you mean. I know it cannot run the drill or chia. I don't know about the FP or globe.

The johnsons I am refering to are simmiler to the ones in FP gearboxes. The RPM tops off around 14,000 on a good battery.

-Greg The Great

Greg, sorry that I haven't answered the question yet. Since I haven't had the time to look at the data needed to give you a correct answer, I thought it would be best to tell you what I would look for. Like Sandrag, I remeber a really tiny Johnson motor. Which year's kit did the big one that you are refering to come in.

First, Bduggan04 said that it was ok based on the 2002 manual. If the Johnson motor you are refering to came in 2002, then you are ok. If you want to verify it, you can get the old manuals through archive.org or search chiefdelphi, since Nate Smith has posted links to old manuals before.

If it's not mentioned in the 2002 manual, or a different Johnson motor was used in 2002, then you need to find the specs for the motor you are using. Places to look for the specs are the manual for the year it came in the kit, team updates from that year, searching chiefdelphi posts, and chiefdelphi whitepapers.

If you can't find the specs from there, you can try the manufacturer. That may be hard though.

The main thing that you are looking for is what the stall current is. If it draws more then about 20 amps when stalled, you shouldn't use it on a spike.

It is not out ofany years kit... They are Johnson 12 Volt DC motors that operate at 14000 RPM, they are brush motors. I do notr have any specks on the motors, other than that they have been used in Fp power wheels gearboxes. I believe they are the same type motors that FIRST issued us in 2K3 for the FP gearboxes. I do not believe the Amps are above 20 when stalled... They are FP motors (99.999999% sure). Can an FP be run to a spike?

Thanks,

-Greg The Great

No, a Fischer Price motor can not be run off of a spike. Its stall current (if I remember correctly) is in the range of 60+ amps.

Anything can technically be run off a spike. Just don't expect to run it at stall for long, or last very long. For the most part, you can run any motor off the spike except the Drill (any year) or the CIM. There's too big of a chance that you will most likely exceed 20A for a long period with these motors.

The FP and van door motors are questionable, but they should work. Just try not to stall the motors very often. The FP motor draws 57A at stall and the van door (any year) is 40A. Basically, plan your motors to only use 20A of the stall current. The ratio of the usable torque can be figured out as 20A/Stall current * Stall torque. You will still see the same free speed, but only expect to produce that amount of torque in your calcuations for extended periods of time (greater than 1 second)... The spikes can handle larger currents for short bursts, but not for very long...

As suggested from 2002 year (manual), put an auto-resetting 20A breaker on the spike to replace its 20A fuse... that way you won't have to deal with blowing and replacing fuses all the time...

Yeah, what I am planning on doing is have the motor pull a chain linked thing I put together that releases a compresses PVC tube, the motor will only have to run for less than a second, I dought it would ever pop the 20A breaker. What do ya think Jdnake?

-Greg The Great

Popping fuses...
 

I think you are likely to pop a lot of fuses.

The in rush current alone may be enough to pop a standard fuse.

I think that you could probably get by if you replaced the fuse with a circuit breaker but you are still walking on thin ice.

You will have to have the motor very lightly loaded in order for it not to have repeated tripping problems.

You will be temped to use the 30 Amp breaker. Again, You can probably get by, but you are on thin ice. One problem with this is that the relay itself is not rated for high current. It is easier than you'd think to weld the contacts on this type of relay.

Victors are so much nicer for this type of application. Perhaps you can ask around for teams with old 883's to sell?

I know Chief Delphi had a boatload of them at one time (we used them in our old Chief Delphi Invitational RC boxes), but I think we are more or less out of stock. I can't be sure but I THINK we don't have that many left any more.

Joe J.

Well if you did try it out, the worst that can happen (assuming everything is properly connected) is that you can blow some fuses. Get other mentors from your team to confirm that everything is properly connected and then see what happens.

I personally would never control any motor with a spike. The Victors provide soooo much more grace in that they can gradually speed up and slow down.

True, but the Victors are also considerably more expensive, and you don't always need one for every task. Also, some competitions (like OCCRA, for example) limit the number of Victors you can use, so sometimes you have to make a Spike drive a motor. When it's the only thing available, a spike can do the job, even if it's not the best possible tool.