I have a 5 hp motor that powers the hydraulic leveling system on my Eagle. I have a 13 KW generator to power the coach. I know that in theory the generator is not big enough to start the motor but for 11 years it has. A couple of years ago I changed out my trace inverter with a magnum and the best I can remember that is when the 5 HP motor became harder to get started and has gotten worse over time. When I start the generator I have a timed relay to let the generator come up to full power before things turn on. Then 2 smaller ( one of them is 1 hp ) cooling fans come on, The inverter comes on and starts charging and if the system is cool the electric element in the Aqua Hot comes on. Then I start the leveling system. The electronic gurus at this point are have a heart attack. I think I can use a smaller ( 3 HP ) motor to power the leveling system or for less bucks I can put a variable frequency drive in the system. Will that help the starting problem? Or what else can I do without tearing the bus apart and start over. I don't want to do this as I still building the second conversion.
Thank You Wayne
Wayne give thought to changing the motor over to DC current a 5hp starter motor is easy to find
I would think a 13k generator has plenty of power to start a 5 HP motor. Maybe you should change your start up procedure from using the inverter and just start the generator and once you are level shut the genset down. The inverter then takes over. Or am I missing something?
--Geoff
Geoff, From what I can figure out is when the motor starts there is not ( for lack of better words ) enough in rush of power to get the motor started when on the generator. When on shore power it starts fine. I have the system torn apart at this time and can't test your theory. Does anyone know if I can put larger capacitor on the motor to help this. Thanks Clifford but that means a lot more work and and want a easier fix .
Thank You Wayne
I would give the larger starting capacitor a shot then,if you have the start/run capacitor you can rewire it to a 2 capacitor system fairly easy,electric motors are older people they get weak and need a little extra kick
Just curious but what leveling system requires a 5hp ac motor, is this a home built leveling system ?
Rusty Huggy has hydraulic levelers on her and I have no problems using them on a 10 k generator.
What do you have on that IGGLE.
uncle ned
PS are you coming to NC this summer and do i need to get some more spring water.
Steve It is a home built system made from parts of an old bridge deck finish machine I had laying around the cylinders are from other pieces of equipment I had. I tend to over build things. The bridge deck finish machine used a 25 horse motor so I guessed a 5 horse would work and it does except now the generator does not like it.
Ned. We will be at NC if I have to use railroad jacks to level the IGGLE. :) I will pass on the Spring Water. The doc says if it tastes good spit it out and that includes spring water. If I knew I was going to live this long I would have taken better care of myself. See you in a couple months
Wayne
If the 5hp motor starts on shore power I would say something is wrong with the genset. My 8kw genset was having power issues and after going through the entire book trouble shooting procedure it turned out to be clogged injector tips from sucking exhaust smoke into the air intake. That was not in the book.
--Geoff
You could probably get a one hp motor motor to do the job. Just would take longer to level. Is your system trying to draw the extra from your battery pack? Maybe batteries are getting weak.
I have an oil filter crusher that handles full size truck and bus oil filters. It came with a 1hp motor and turns a 22 ton hydraulic pump. The motor quit, so I bought a 1.5hp motor from Harbor Freight. It would not turn the pump. Took it back and got the 2hp. It wasn't strong enough either. Both 120v.
So I took that one back and got the 3hp 240v motor. That one worked! My point? American vs Chinese.
--Geoff
My little 3500W emergencies-only generator won't comfortably start my on-board air compressor once it's at pressure if I plug it straight in to the generator. If however I connect it through a 100 ft 12-ga extension cord it will start better. Figure that one out! I remember reading about something like that on the NAWS forum, so I tried it and it works. Don't ask me why. I think it's something to do with Power Factor - my compressor has a lousy PF (like most capacitor-start Chinese motors), somewhere about 0.6-something according to my Kill-A-Watt meter. I wish I better understood all that EE stuff!
John
I think an added capacitor is the answer. It will help to absorb the inrush of current at start up.
I believe the added 12 ga. extension cord is doing something parallel but using resistance to absorb inrush instead of capacitance. I'm not an electrical engineer but it sure sounded good IMO... :-)
Quote from: luvrbus on March 16, 2017, 07:54:41 AM
I would give the larger starting capacitor a shot then, if you have the start/run capacitor you can rewire it to a 2 capacitor system fairly easy, electric motors are older people they get weak and need a little extra kick
they get harder to start if it is cold too or a load/partial load is on it. is there a relief valve?
should be a tag, FLA and LRA...Locked rotor and full load amps...you can tell how old or worn out it is with a clamp on amp meter.
for the duty cycle, a DC motor works. seems old Ford starter motors and relay are what we built snow plow hydraulics out of.
Quote from: Geoff on March 16, 2017, 07:09:46 AM
I would think a 13k generator has plenty of power to start a 5 HP motor. Maybe you should change your start up procedure from using the inverter and just start the generator and once you are level shut the genset down. The inverter then takes over. Or am I missing something?
--Geoff
Geoff, I don't think you're missing anything, I think Wayne is. He forgot to tell us what voltage his 5 hp motor is. If it's 240 volt then his 13 kw should start it without missing a beat, but if its 120 volt, that would put a serious strain on things. How-bout-it Wayne, what voltage we talkin ?
It is 240 volt. If you talk to the guys at Wrico they say the generator will not start the 5 HP motor. It has been starting it for 10 years now it won't. The generator has 121 on both legs and 242 across the legs and runs at 61 Hz. when you try to start the motor it will drop to 80 volts. The inrush talk is making more sense to me. Do capacitors get weak I think Clifford hinted at this.
Thank You Wayne
When my generator wasn't running right it would start and put out full power but when I tried to run more than one roof air it would kill the engine. As mentioned before, it turned out the injectors needed to be rebuilt. After that I could run three airs, the electric water heater, and everything 120v and the generator would handle it all.
--Geoff
Capacitors do get weak, and yes I think Cliff hit it with the motor start capacitor. That's a cheap repair, even if it goes beyond that...
Wayne, you can up the voltage with a different starting capacitor it doesn't have to be as same as the old one talk to your supplier and they can fix you up
How about replacing the capacitors with new and see if that doesn't fix it. They should have the specs marked on them.
Maybe the generator finally decided it wasn't going to do what it wasn't supposed to do anymore!
No all kidding a side, I tend to thing Geoff is on the right track if it starts fine off the shore power but not the genny!
;D BK ;D
Quote from: Geoff on March 17, 2017, 06:40:12 AMWhen my generator wasn't running right it would start and put out full power but when I tried to run more than one roof air it would kill the engine. As mentioned before, it turned out the injectors needed to be rebuilt. After that I could run three airs, the electric water heater, and everything 120v and the generator would handle it all.
--Geoff
That's interesting to know, Geoff, and it seems to me to be something that everyone should keep in mind when considering any "weak generator" problem. Does the same thing apply to the generator head? I'd think that if you had windings or brushes or similar parts that were causing less power from one leg, it would work the same way -- is that right?
Quote from: Oonrahnjay on March 17, 2017, 08:34:15 AM
That's interesting to know, Geoff, and it seems to me to be something that everyone should keep in mind when considering any "weak generator" problem. Does the same thing apply to the generator head? I'd think that if you had windings or brushes or similar parts that were causing less power from one leg, it would work the same way -- is that right?
I have had generators that simply quit charging and the engine ran okay, and I bought a portable gas 7kW from Costco that would only put out enough power to run a 100 watt light bulb but not anything like my 240v hot pressure washer. The engine would run but the pressure washer would just humm. I took it back and got another generator and it ran the pressure washer just fine. You could hear the generator bog down when the pressure washer was tuned on but it held the load.
Now with my 8kW diesel genet for the bus, when a load would kill the engine I called the company that built it and the owner told me to run through the generator head troubleshooting procedures in the book to test the generator head. I did every one and even had to buy a new test meter to do it. The owner of the generator company thought it was the generator head that was killing the engine, but all ny testing showed the generator head was good. So that is when I started checking out the engine and decided to pull the return line from the injectors off to see if I had good flow. I had good flow, but the diesel fuel coming out was black!
So I pulled the injectors and saw a lot of carbon build up on the tips. The air cleaner was also black. So I realized I had the air intake too close to the engine exhaust and the engine was pulling in the smoke from a clogged air filter. I simply replaced the injector tips and air cleaner, put it back together and my low power problem was fixed.
So this does not tell me if a bad generator head will slow down an engine, but the owner of the genset company thought it was the problem, so based on his extensive experience I have to say it is possible. But it hasn't happened to me. Rusty has not indicated he has done any testing of his 13kW genset, whether it bogs down when it won't start the 5hp motor or if it keeps running the same . If it keeps running the same I would guess he has something wrong with his generator head. A very simple test is to take the bus to a shop that works on generators hand have them do a load test
--Geoff
Geoff has some valid points. Everything else that is on the generator works fine ( two 13000 roof airs 2800 inverter heating element in the water heater. I have heard every word you said. I now have two things to look at the generator and the motor. I think I will start with the motor. If that is not it then I will look at the generator but will do one at a time so I know what the problem is.
Now back to my original question Does anyone know if a variable frequency drive will help with the lack of inrush of power from the generator.
Thank You Wayne
I do not know anything about your drive question. Just wondering, are the references to upgrading the capacitor the same as installing a hard start kit?
Quote from: Lin on March 17, 2017, 02:03:41 PMI do not know anything about your drive question.
I'm also baffled ... (yeah, not unusual). Is your 5-Hp motor a 120V, single phase motor? Also, the plain conversion says that 13Kv is approx. equivalent to 17-Hp; if the 13Kv generator is working anything like properly, why wouldn't it start and run a 5-Hp motor? ??? ???
But to your question about VFDs, here's what I found first:
https://en.wikipedia.org/wiki/Variable-frequency_drive
It seems to me that these are devices used to *lower* the power to a motor once it's running (to save juice) and not a device to "supercharge" power so as to start an overloaded motor.
And I don't understand your automatic-powerup sequence. Do you mean that you're running air conditioners plus whatever the inverter will pull as charging power when you're trying to start your leveler motor? If so, I'd guess that changing that would be a lot more useful than adding some hi-tech electronic control to the leveler motor. But, don't pay much attention to me, I'm baffled!
Didn't see that anyone answered one of your original questions, using a variable frequency drive will definatly solve your motor starting problem, it eliminates the high inrush current of the motor.
Quote from: rusty on March 17, 2017, 06:02:30 AM
If you talk to the guys at Wrico they say the generator will not start the 5 HP motor.
Thank You Wayne
Did the guys at Wrico say why the generator will not start the 5 HP motor ? That just doesn't sound right.
Everything I read here points to the 5 hp motor as the problem, not the generator. Did you check the amps at startup ? If the volts drop to 80, that means the amps must be way high. You should have about 48 amps at startup and around 23 running. (not counting the other loads) I see no reason a 13kw shouldn't handle that, even with the extra loads it should be ok. I agree that checking the capacitor would be the first place to start. Don't forget to discharge it first
Okay. In my previous post I told how a Costco 7kW genset wouldn't run my hot pressure washer and it was a defective generator head. I looked at my pressure washer and it has a 5hp motor that pulls 22 amps@240 bolts. So a 13kW generator should have no problem. I don't know who you talked to at Wrico that said a 13kw wouldn't start a 5hp motor but it had to be some kind of mis-communication.
--Geoff
Thank You Bruce. I will let all know what I find
Wayne
Quote from: rusty on March 20, 2017, 06:13:52 AMThank You Bruce. I will let all know what I find
Wayne
Is your 5 Hp motor three-phase? The only VFD's that pop up on a Google search for 5 Hp seem to be three-phase and $500 - $600 - $700. ISTM that a VFD to start a motor is like gold plating a Pinto's wheels so they won't rust as it sits behind your barn with no engine in it. Please do let us know what you find/how you fix this.
(The "other Bruce")
Quote from: Oonrahnjay on March 20, 2017, 06:33:07 AM
Is your 5 Hp motor three-phase? The only VFD's that pop up on a Google search for 5 Hp seem to be three-phase and $500 - $600 - $700. ISTM that a VFD to start a motor is like gold plating a Pinto's wheels so they won't rust as it sits behind your barn with no engine in it. Please do let us know what you find/how you fix this.
(The "other Bruce")
;D :D ::)
That right thar is funny an I don't care who it offends! BTW I wouldn't waste the time plating the wheels, however it wouldn't be a bad idea for the fire extinguisher so it was easier to spot! ;)
;D BK ;D
Quote from: B_K on March 20, 2017, 07:26:53 AM
;D :D ::)
That right thar is funny an I don't care who it offends! ...
Not trying to be a smart aleck, just don't understand the details of making this work without spending hundreds of $$$ for a system that "ought to work" based on the numbers. KISS ...
Quote from: Oonrahnjay on March 20, 2017, 07:50:10 AM
Not trying to be a smart aleck, just don't understand the details of making this work without spending hundreds of $$$ for a system that "ought to work" based on the numbers. KISS ...
I agree with the above. There is either a problem with the 5hp motor or the genset (maybe both). The underlying problem is what needs to be fixed. The problem needs to be fixed as it can only get worse.
--Geoff
Followup, I had the motor checked out and all that was found was the start switch need cleaned. The generator checked out OK. It still boiled down to the inrush needed for the higher torque motors and generators do not supply this inrush. The fix was to use a variable frequency drive to lower the amps required or use a smaller motor. I needed a motor for a planner I have so I got a 3 HP motor for about the same dollars as a VF drive. The amp draw on the 5 HP was 21 and on the 3 HP is 13. Problem solved all works well.
Thank You Wayne
Quote from: rusty on April 07, 2017, 10:28:40 AM... Problem solved all works well.
Thank You Wayne
Good news - glad you got it worked out.