I need help to figuring out for a motor to turn clockwise and clockwise.

Thread Starter

Christopher Wessell

Joined Feb 17, 2018
6
this forum looks like it will be very helpful! And hopefully I can help others also.

I need help figuring out how I can get a motor to turn clockwise for 5 seconds and then 5 seconds counter clockwise...

My motor is reversible so would need something to switch the currents over every 5 seconds.

I have a geared motor I want to run half a turn one way and then half a turn back to guide a hosepipe left and right as it is wound up on to my motor powered hose reel.

I am thinking some kind of adjustable alternating relay... like a window wiper relay... but where and how should I set this up?
 

wayneh

Joined Sep 9, 2010
17,498
First, welcome to AAC!

Rather than reverse the motor, maybe the solution could be mechanical? I think wiper motors just turn one direction, for instance, and use a mechanism to convert to oscillating the wipers.

It's not a problem to reverse current to the motor, that's done with a circuit called an H-bridge, which you can find ready-built on eBay for cheap. Just think about controlling it so that you slow or stop the motor before hitting it with reverse current. Maybe that's not an issue for a small motor but it could be with a big one.
 

MisterBill2

Joined Jan 23, 2018
18,464
First, welcome to AAC!

Rather than reverse the motor, maybe the solution could be mechanical? I think wiper motors just turn one direction, for instance, and use a mechanism to convert to oscillating the wipers.

It's not a problem to reverse current to the motor, that's done with a circuit called an H-bridge, which you can find ready-built on eBay for cheap. Just think about controlling it so that you slow or stop the motor before hitting it with reverse current. Maybe that's not an issue for a small motor but it could be with a big one.
WayNeh is certainly correct, and besides that, it will take a fair amount of power to move that hose back and forth as it is being wound onto the reel. I suggest using your gearmotor to drive a constant velocity cam to move the hose back and forth to produce a level wind.
However, given the environment of the typical hose reel system, My suggestion is forget the motor and use a mechanical arrangement to get the hose to wind evenly. Or learn to do it by hand. I have seen a large number of hose reels disposed of in the past year, so my thinking is that they all have some intrinsic flaw, since so many of them are being discarded.
 

Thread Starter

Christopher Wessell

Joined Feb 17, 2018
6
First, welcome to AAC!

Rather than reverse the motor, maybe the solution could be mechanical? I think wiper motors just turn one direction, for instance, and use a mechanism to convert to oscillating the wipers.

It's not a problem to reverse current to the motor, that's done with a circuit called an H-bridge, which you can find ready-built on eBay for cheap. Just think about controlling it so that you slow or stop the motor before hitting it with reverse current. Maybe that's not an issue for a small motor but it could be with a big one.
Hi Wayne’s I initially thought to use a cam and sliding arm on a fixed point to convert the single rotation to side to side and haven’t ruled that out entirely yet but just exploring all avenues and thought maybe if this is achievable reversing the motor with the right timing then it might simplify things mechanically speaking and also save space.

If I see what you mean with regards to the suddenly alteration in movement with the polarity change. If the circuit could allow I thought maybe a slight delay in the change of direction.
 

Thread Starter

Christopher Wessell

Joined Feb 17, 2018
6
WayNeh is certainly correct, and besides that, it will take a fair amount of power to move that hose back and forth as it is being wound onto the reel. I suggest using your gearmotor to drive a constant velocity cam to move the hose back and forth to produce a level wind.
However, given the environment of the typical hose reel system, My suggestion is forget the motor and use a mechanical arrangement to get the hose to wind evenly. Or learn to do it by hand. I have seen a large number of hose reels disposed of in the past year, so my thinking is that they all have some intrinsic flaw, since so many of them are being discarded.
Heya my idea is that if I have some kind of mechanism to ensure the hose winds on nice and evenly then this will be great as I am intending to use a remote as well as the push button I have to start / stop the motor that drive the reel.

My hose is 8mm reinforced microbore It’s in my window cleaning van as the hose I use on jobs for delivering the pure water to my poles for cleaning the windows. The electric wind up is great and saves a lot of time winding up up to 100 of meters of hose each job but my thinking is it will be very handy to be able to have it winding in on remote as I approach the van. Saving more time!

The problem is it needs to wind up evenly by itself so something is needed to slowly guide the hose 1ft left over 5 seconds and back 1ft over 5 seconds over and over a slight delay of half a second each way would be fine I think.

I have a geared motor which I have purchased from eBay recently it is plenty strong enough but at 20rpm I think it is slightly to fast to will have a work out and get one slower. Which should have more torque also.
 

Thread Starter

Christopher Wessell

Joined Feb 17, 2018
6
First, welcome to AAC!

Rather than reverse the motor, maybe the solution could be mechanical? I think wiper motors just turn one direction, for instance, and use a mechanism to convert to oscillating the wipers.

It's not a problem to reverse current to the motor, that's done with a circuit called an H-bridge, which you can find ready-built on eBay for cheap. Just think about controlling it so that you slow or stop the motor before hitting it with reverse current. Maybe that's not an issue for a small motor but it could be with a big one.
 

Thread Starter

Christopher Wessell

Joined Feb 17, 2018
6
If I was to use this a h bridge how could I set it to change polarities every 5 secs continuously? I think the sudden change in polarity should be okay as motor is only small. It will always be under load with the high gearing which should help also?

Does anyone have any links of the gadget I need which will be suitable? It needs to remember the settings and activate in sync with the reel motor.

Power supply is a 12v leisure battery.
 

AnalogKid

Joined Aug 1, 2013
11,037
Motor voltage?
Peak motor current?

Is this the idea:

Apply power
Start motor in one direction
Motor runs for 5 seconds
Stop motor briefly
Start motor in the other direction
Motor runs for 5 seconds
Stop motor briefly
Repeat

If so, then over time the hose moving mechanism will eventually be jammed up against one side or the other. There is no way to guarantee that the motor starts up and runs with the exact same speed and torque profile every time in both directions.

A better way is to have limit switches on the mechanism the motor is driving. The switches tell the system when to reverse the motor based on the traveler's actual position rather than a guess based on average timing.

ak
 

Thread Starter

Christopher Wessell

Joined Feb 17, 2018
6
Motor voltage?
Peak motor current?

Is this the idea:

Apply power
Start motor in one direction
Motor runs for 5 seconds
Stop motor briefly
Start motor in the other direction
Motor runs for 5 seconds
Stop motor briefly
Repeat

If so, then over time the hose moving mechanism will eventually be jammed up against one side or the other. There is no way to guarantee that the motor starts up and runs with the exact same speed and torque profile every time in both directions.

A better way is to have limit switches on the mechanism the motor is driving. The switches tell the system when to reverse the motor based on the traveler's actual position rather than a guess based on average timing.

ak
Hey Ak

Ah I see that would be pants. Your idea is great though thanks. Just so I am on the right track your saying a switches that can be adjusted mechanically which both change the polarity when the arm reaches the set limit one way and then when it reaches the set limit the other way the motors polarity is switched again and so on... until it’s off and the it will restart what ever way it was before and then carry on again.... sounds like that would work to me with some thought on how the switch’s / circuit would need to be configured.
 

MisterBill2

Joined Jan 23, 2018
18,464
Heya my idea is that if I have some kind of mechanism to ensure the hose winds on nice and evenly then this will be great as I am intending to use a remote as well as the push button I have to start / stop the motor that drive the reel.

My hose is 8mm reinforced microbore It’s in my window cleaning van as the hose I use on jobs for delivering the pure water to my poles for cleaning the windows. The electric wind up is great and saves a lot of time winding up up to 100 of meters of hose each job but my thinking is it will be very handy to be able to have it winding in on remote as I approach the van. Saving more time!

The problem is it needs to wind up evenly by itself so something is needed to slowly guide the hose 1ft left over 5 seconds and back 1ft over 5 seconds over and over a slight delay of half a second each way would be fine I think.

I have a geared motor which I have purchased from eBay recently it is plenty strong enough but at 20rpm I think it is slightly to fast to will have a work out and get one slower. Which should have more torque also.
I see! I was thinking of the garden hose reels that a lot of folks give up on. Given the application a constant velocity cam with a dwell at each end seems like the best choice, and it could be associated with the speed reduction from 20RPM. There are cam profile generation programs around, and the one cam that I had produced for a project was made from an Excel table of angle versus lift. Your application would need a cam follower, possibly an Osborne Cam follower, running in a slot in a cam, since it will need to push in both directions. An interesting alternative would be a reversing lead screw to drive the hose guide back and forth, but I don't know any leadscrew grinding companies.
 

AnalogKid

Joined Aug 1, 2013
11,037
Just so I am on the right track your saying a switches that can be adjusted mechanically which both change the polarity when the arm reaches the set limit one way and then when it reaches the set limit the other way the motors polarity is switched again and so on... until it’s off and the it will restart what ever way it was before and then carry on again.... sounds like that would work to me with some thought on how the switch’s / circuit would need to be configured.
The standard way is that the switches control a relay or two, and the relays control the motor. Basically, the two switches act to set and reset a flipflop. The flipflop can be one 3- or 4- pole relay, or two smaller relays, or an impulse relay, or an electronic circuit driving a relay. Most motors don't like being slammed from one direction to the other instantly, which is why I mentioned a small delay. But the delay makes the control system a bit more complicated, requiring one relay for motor reversal and something else (like another relay) interrupting power briefly to let the motor come to a rest before running it in the other direction. Depending on the motor, that might take so long that it messes up the hose reeling flatness.

Motor size, motor power, time for motor to shut down to 0 rpm?

Where are you located?

ak
 

Jonlate

Joined Dec 21, 2017
118
I think the window wiper way is the way to go.
My wipers stop in the same position every time and don’t over run!
With the motor only going one way it makes things easier, and a window wiper motor runs on 12v and had good torque.
The sweep will be way to big, but if you make the arm, that would have the wiper blade on it smaller, then it won’t travel so far.
Then you would only need to join put a switch on the live wire to stop and start it.
 

AnalogKid

Joined Aug 1, 2013
11,037
The window wiper way (unidirectional motor and augmented cam) is very simple electrically, and is much less stress on the motor. However, the velocity profile across the span is not constant, something that is kinda important when spooling a constant-diameter hose onto a constant-speed drum. If the TS can handle that, great; if not, we got relays.

ak
 

Tonyr1084

Joined Sep 24, 2015
7,899
Some things I'm reading that kind of bother me. First and foremost is what people consider a "Small Motor". Well, a small motor (to me) is something like what is found in an old tape deck, or CD player. I have a garage door motor (DC) that is reversible and it's relatively "Small", however, I don't think it would like being slammed from CW to CCW (Clockwise to Counter Clockwise) repeatedly.

Also, the windshield wiper system: To me that has flaws too. The speed of the arm going across the middle of its travel will be faster than at either end. Windshield wiper motion is analog, not digital. So in my way of thinking, using the wiper system would leave gaps in the hose reel in the middle and will tend to double over the hose on either end.

Initially, I was thinking the way others were thinking (or so I got that impression) that we were talking about something like a hose reel system you find in many gardens. Those have a cam that has slots (I can't explain) but some sort of following device controls the back and forth motion of the rewinding mechanism. I'm sure that would not suit your needs.

I liked what AK had to say about limit switches, but that also has some drawbacks. Suppose you unwind some amount of hose. The last known drive of the rewind motor was known to be sweeping (lets say - Left). But you unwind past the point where the last known position was set, and you begin winding your hose. You could end up with hose doubled up across only half way across before the motor starts back in the opposite direction.

I didn't join this discussion because I have a solution, I joined because I see problems with the proposed solutions. What I have to GUESS at what might be a workable solution would be to put something like a magnet on the main hose reel along with a couple hall sensors and to use a microprocessor (µC). The µC needs to know when the hose is fully wound, how much hose has been unwound and at what point it needs to start driving from side to side so the hose can be wound back without doubling (crossing over) a previous wind. I still like the limit switch part of it, as it prevents over-travel, and potential jamming of the mechanism, which could lead to self destruction.

As for reversing a motor without slamming it from CW to CCW or back, using a simple RC delay circuit to cause a period of rest between CW and CCW and back. The delay circuit could power a relay that doesn't apply power until it times out. And with an adjustable knob you can set the delay to best suit the speed in which your hose is rewinding and needs to delay before your cam mechanism (or whatever you decide) starts traveling again.

I wish I were better with electronics design, this sounds like an interesting project. It's over my head, so I don't have a solution for you. But I know the guys here - once they get on the right track - will be able to help you in many ways. OR you'll come to the conclusion that your project is not worth the effort. I understand rewinding the hose so it doesn't exceed the diameter of the bobbin its rewound upon. Haphazardly rewinding the hose will result in exceeding the bobbin diameter and present the potential of tangles when unwinding. I've seen that happen before.

{EDIT} Thanks AK, you beat me to the point about the wiper speed. By less than a minute.
 

Tonyr1084

Joined Sep 24, 2015
7,899
Real world experience with reversing direction motor: My mother-in-law has a washing machine that has no gear drive system. The motor directly drives either the agitator or the drum. The motor is powered by an inverter (or so the paperwork calls it). One moment the motor is spinning one direction then the next moment it's spinning the other. I know this because her machine had a failure, a mode shift coil failed. When I repaired the coil (fusible link blew, no sign of overheating whatsoever) I noticed that the mechanism used that shift coil to either connect the drive motor to the agitator or to the drum. When her coil failed the drum would try to spin one direction then the opposite. And the motor didn't seem to mind that whatsoever.

I don't know what voltage that motor was driven at. On the off chance it's driven by low voltage then this sort of motor might lend itself well to driving the rewind arm back and forth. Using a µC to decide what position it needs to be in and using the programming to input the delay, that might be one solution. At least that's the best I can offer with what little I know about these things. Hey! Sometimes out of the mouths of babes. (No, I'm not a babe. Just inexperienced, that's all I'm saying)
 

ElectricSpidey

Joined Dec 2, 2017
2,776
Well electro-mechanical is kind my speciality, and I would say this is a job for a liner actuator.

Converting rotation to uniform linear motion is a real bugger, unless you really know what you are doing.
 

AnalogKid

Joined Aug 1, 2013
11,037
I don't know the name for it, but I remember fishing reels with a traveler mechanism geared to the spool, that automatically reversed direction at each end and a guide for the line. It was a round bar about 1/4" dia. or so, with two criss-crossed tracks machined into it. I'm sure professional reels have something similar.

ak
 

ian field

Joined Oct 27, 2012
6,536
this forum looks like it will be very helpful! And hopefully I can help others also.

I need help figuring out how I can get a motor to turn clockwise for 5 seconds and then 5 seconds counter clockwise...

My motor is reversible so would need something to switch the currents over every 5 seconds.

I have a geared motor I want to run half a turn one way and then half a turn back to guide a hosepipe left and right as it is wound up on to my motor powered hose reel.

I am thinking some kind of adjustable alternating relay... like a window wiper relay... but where and how should I set this up?
All the wiper motors I've seen had a bell-crank/crankshaft arrangement to produce reciprocating movement.

How you reverse a motor depends on which type. With PM brush motors you simply reverse the current - with wound field brush motors, you have to reverse connections to the brushes.
 
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