#1
IP: 108.31.90.116
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Alternator Curves
Has anyone come across a set of output curves for the Mando (now API) 55 Amp alternator that MMI sells showing output vs RPM and temperature? I've spent some time digging on the web, and found the manual, but haven't been able to turn up a set of curves yet.
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@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#2
IP: 24.152.132.65
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Ed,
This graph is for the Arco 60050 which is listed on the API site as the same as their 55A as well as the Mando. What ratio are you using to calculate alternator RPM (necessary for the graph to be meaningful)?
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#3
IP: 97.93.89.70
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How much?
Neil, would the regulator not have a lot to do with RPM vs output? Or is the graph just the "capability of the alt" itself?
Dave Neptune |
#4
IP: 24.152.132.65
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The graph presents alternator amperage capacity while a regulator controls the output voltage. Tweaking the output voltage up on manually adjustable regulators* would result in higher amperage output (still within the limits of the graph) but at the risk of high voltage system damage at some point. Our EI ignition system seems to be one of the more sensitive due to massive dwell and its effect on the coil.
*note that the only adjustment available on manually adjustable regulators is voltage because that's all they regulate. Further comment on the pulley ratio: The standard Motorola 35A alternator spins at 1.75x engine RPM. However, my Delco 10Si spins at 1.5x. It's important to measure the pulley diameters (drive and alternator) and calculate your own ratio (drive diameter / alt diameter) before using the graph. Since Ed brought this up I studied the output curve for my alternator and it revealed something quite interesting. When I bought the alternator it was sold as a 100A Delco 10Si. As part of a necessary internal regulator replacement to tame down the voltage I had it dyno tested. At 2000 RPM (alternator) the output measured a little over 50 amps. Studying the graphs for various Delco alternators, the highest 10Si shown is a 72 amp model and its output at 2000 RPM is only 22 amps while the 12Si 94 amp model is right at 50 amps according to its graph. Since both the 10Si and 12Si are the same physical size and appearance I'm calling mine a 12Si from now on based on measured performance and published data. Applying the pulley ratio discussed above to the 12Si 94A graph, I can expect up to approximately 72 amps output at 2000 engine RPM. Of course I'd have to be abusing my batteries to ever reach that output.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 03-27-2016 at 04:05 PM. |
#5
IP: 107.0.6.242
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The graph in post #2 is very instructive. Most of the available amperage of both alternators kicks in around 4000 rpm. If you cruise around 2000 engine rpm, the 2:1 ratio will set you up nicely.
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#6
IP: 107.0.6.150
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As Neil has correctly pointed out, the regulator regulates voltage; amperage is based on what the batteries are calling for. The problem I have run into with steep ratios, alternator to engine, is the load on the engine at start up (before the engine reaches operating temperature) can be substantial and makes me uncomfortable, which is why I abandoned 3:1 and went to 2:1. If someone could come up with a way to delay full amperage output until the engine is warmed up I would consider going back to the 3:1.
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#7
IP: 71.59.125.65
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Assuming an alternator is installed, as mine is, how would I go about measuring the actual amp. output of the alternator? I had my alt made for me by a local alternator shop. The owner/mechanic/wizard knew our atomic 4 engines, the limits on revs and existing drive pulley size. I was asking for 100 amps, which he said was almost impossible to do, partly because of heat generation by the alt itself. He told me he would "take care of my need", then charging my 2 - 4D batteries and powering up my inverter to run the electric water heater. What ever he built it seems to be doing a fine job, I just refer to it as a 100 amp out of habit. I do not run an amp meter, partly because the original was to small and partly because it the location of the gauges would more than double distance and resistance of the charging wire- from alt. to meter - battery switch / battery.
My inverter constantly displays my voltage, which serves to keep me updated on the voltage output of the alt. It would be nice to be able to know what amperage I am putting out at set RPMS. Just for the sake of knowing. Is this something I could test with an amp meter from alt to ground? Thanks
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Bill 1974, Tartan 30, Unchained Melody www.CanvasWorks.US |
#8
IP: 24.152.132.65
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With a shunt type ammeter distance is not a factor. Here's one that will suit your needs. It installs in the alternator output wire.
http://www.ebay.com/itm/like/3316128...&ul_noapp=true Do not be alarmed if the reading seems low. Alternator output is determined by the connected battery's State of Charge so unless the battery is dead flat the alternator will probably not be operating at full capacity.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 03-27-2016 at 05:02 PM. |
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BadaBing (03-27-2016) |
#9
IP: 73.255.216.151
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Hanley, does not the regulator control the field of the alternator. You can switch the wire that goes from the regulator to stop the alternator from charging. At least that is the way I understand it.
On my battery select switch there is "field disconnect" terminals. The purpose is to break the field and stop the charging while changing batteries in order to prevent damage to the alternator. I have a Balmer ARS III regulator. It is made to delay the alternator from charging for a short time. It is about 30 seconds to a minute. I can here when the alternator kicks in after start. I have been threatening to add a field switch for 15 years. This way I could let the engine warm a bit. |
#10
IP: 107.0.6.150
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Quote:
Last edited by hanleyclifford; 07-13-2016 at 08:23 PM. |
#11
IP: 73.255.216.151
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Hanley, why not just have a switch? on/off. You could even have a timer. After running the batteries down, there is quite a load on the engine. Not something I like to do to a cold engine.
Wish I could program that regulator to hold off for 5 minutes. |
#12
IP: 24.152.132.65
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Easy to do with a delay-on-make relay such as McMaster-Carr 77055K736. You realize you'll be running off battery power only during the warm up period.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#13
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I guess if it started on battery, 5 more minutes wont make a difference. Thanks Neil.
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#14
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I use the same timer (different timing range though) on my alarm system and it has performed flawlessly for years. I can't stand buzzer noise on startup like all those smelly diesels. From ignition on to arming my alarm is 10 seconds.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#15
IP: 107.0.6.242
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I had a look at that delay switch Neil recommended, and I like the idea of a delay. However, that only solves part of the problem; the other part is the sudden enormous output at switch-on. I would also like to increase amp output in stages after warm up and that might be complicated.
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#16
IP: 108.31.90.116
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Quote:
The chart is half of what I'm looking for. The other half is the family of curves for various temperatures. I'm in the early stages of converting my MMI-purchased Mando 55 to external regulation, probably using one of the Balmar smart regulators (but that's not cast in stone). Alternator output falls off with temp, and too hot a temp will cook the alternator. I'm concerned about cooking the Mando by pushing it too hard for too long, as the smart regulators can be prone to do in the bulk charging phase. Some of the Balmar regulators include temperature sensing and limiting for the alternator temp. I just replaced my two Dekka Group 31 Gel cells after 12 years of service, so I was very pleased with them, and went back in with another 2 Dekka Gr-31 gels. For the past 6 years, my pattern has been mostly day or weekend sails, with an occasional 1 or 2 week trip thrown in. So the bulk of the charging has been on shore power, with a 3-stage smart regulator properly programmed for Gel cells, and temperature compensated for the battery temp (very important for Gel Cells). Given the exceptional life I got, it seems to have worked properly. This fall, my pattern will change drastically, as we head down the ICW from the Chesapeake to Florida. This will entail large amounts of motoring, so I want an alternator regulator that will properly switch to a float voltage when the batteries are charged, as gels are particularly susceptible to irreversible damage from overcharging. But then once in Florida, we will be jumping over to the Bahamas, and spending up to 3 months over there, largely on the hook or sailing. For this, We will need an alternator regulator that does proper, temperature-compensated bulk and acceptance charging phases to minimize the amount of daily engine run time required to make up our daily power budget (consisting largely of the refrigeration) of about 60-70 Amp-Hours per day. According to my measurements made on our 1 or 2 week cruises, the existing internal regulator is taking about 4 hours of engine run time to bring the house bank from 50% state-of-Charge (SOC) to 80% SOC, which is roughly where the transition occurs from bulk charging to the slower acceptance phase. With a properly configured smart regulator, this time should be closer to 2 hrs, which will translate into a significant savings in fuel. But its going to have to be limited by the alternator temperature, hence the need to know the Mando Alt's temperature curves, or at least an equation for derating it by temperature. Quote:
The higher-end Balmar external regulators incorporate both a start-up delay, and a ramp-up feature. But they're pricy.
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@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 Last edited by edwardc; 03-28-2016 at 01:12 AM. |
#17
IP: 70.192.34.133
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Time Delay Relays
The McMaster 77055K736 relay is rated for 1 amp at 120vac. For an alarm circuit this is satisfactory. However, field current ranges from zero to 5+ amps for most alternators (my 50 amp Paris-Rhone has a 5A field current at 50 amps output). That high a current should destroy a 1 amp relay.
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#18
IP: 24.152.132.65
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Quote:
I'm sure you've analyzed your needs down to the gnat's hair but if I were planning prolonged cruising away from the dock with refrigeration I'd be looking at solar for sure, perhaps an engine driven refrigeration compressor with holding plates like the BVI charter fleet used successfully way back when I was there. Their charter instructions called for one hour of daily engine run time and they kept up (batteries and refrigeration) just fine without solar and if my memory hasn't failed completely, this was well before 3 stage smart chargers were popular. About Tac's amperage comment, I didn't consider the amperage specification of the time delay relay I referenced so thank you. However, I could not help but think about the perceived concern of alternator loads during warm up and their significance. Has anyone ever had a problem? Is this an automatic charging relay concern? With my Jurassic manual battery switch system I start and warm up on an isolated starting battery, switch over to the house bank when I am ready.
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Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 03-28-2016 at 10:02 AM. |
#19
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#20
IP: 107.0.6.242
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#21
IP: 107.0.6.242
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The Long Term Objective
in my case is to be able to motor the ICW at around 2000 rpm with a 1700 watt toaster oven cooking supper while maintaining full batteries. If you don't have 2:1 reduction, don't even think about trying to produce that kind of juice. First things first.
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#22
IP: 71.59.125.65
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Surprised I have not done so before but I just measured my acc. drive and alt wheels.
3.85" & 2.37. (these are outside measurements but I think the math will work regardless) That works out to 1- 1.63. I guess I could go a little smaller on the alt but the shop was troubled about slippage. Anyway at 1500 RPM my alt it spinning at 2436 RPM At 1800 max cruising range 2,934. Of course with a heavy load on, it might not be able to reach 1800. After posting my deleted question, (quoted by Hanley ) it occurred to me that when I want aux AC I really don't want to have Katherine or I working in the galley with the engine roaring along at 1500 rpm, to make toast and coffee. Actually the battery bank does a fine job of powering our small 120V needs alone and they seem to be completely, or nearly so, recharged in only a half hour to hour of running time. WE might need a little extra juice for the toaster oven. I'm thinking that "for those special " occasions a less costly Generac will do just fine at $499. if needed at all. The spare 35 amp alt will serve well as a backup if necessary to keep us going, even though it cant meet our aux needs.
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Bill 1974, Tartan 30, Unchained Melody www.CanvasWorks.US Last edited by BadaBing; 03-28-2016 at 10:41 AM. |
#23
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If you have room for that little generator, and have the ability to exhaust safely, and a place to store when not in use (or a way and place to mount it permanently where it can be fueled, started, and exhaust conveniently - that might be the way to go.
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#24
IP: 70.192.34.133
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Cruising with Refrigeration
I have the following setup:
House batteries: Two gp31 105AH AGM batteries in parallel Start battery: One U1R 32AH flooded Balmar 612 regulator for the house bank, with alternator temp sensor. Manual at http://www.balmar.net/wp-content/upl...-2005-2009.pdf Balmar Duo Charge for the start battery Alternator: Paris-Rhone 50 Amp with 2" pulley (2:1 ratio) Solar: Two panels in parallel, with regulator, for 40 watts max Refrigeration: Converted ice box, about 6 ft-cu, with air cooled Danfoss BD35F compressor. Reefer load about 40-60 amp hours per day. I cruise every June for 4-5 weeks, single-handing, always anchoring, never shore power, no marinas except for wine, ice cream and water (haven't figgered out how to change water to wine yet). The rest of the summer is on a mooring with day sails several times a week. The reefer load is by far the biggest boat amp-hour load, even in Maine with water temps rarely above 65°F, and the solar panels give back maybe 50% of that (if the sun's out). If the house bank is discharged 25% or so, the Balmar 612 charges at bulk (starting at 50 amps and quickly dropping off to 35 amps) for 30-45 minutes, then to acceptance for an hour or so before dropping to float. I've never had the 612 cut back field current due to high Paris-Rhone alternator temp (I had a 70 amp Balmar alternator whose case would go over 180°F and the 612 would cut output back as designed). Since we often have no wind here in the summer until about 10AM, I generally motor for an hour or so while transiting, and that recharges the batts. In summary, a) Get the Balmar regulator (it looks like the 612 has been superseded by the 614, generally a sign of a price hike) with alternator and/or battery temp sensor, it Works Fine, Lasts Long Time (old engineering maxim) and is fully adjustable. b) I fully agree with Neil: get one or more solar panels and regulator. My 40 watts is too small, go for more. Last edited by tac; 03-28-2016 at 01:26 PM. Reason: Changed solar ratings from 40 amp-hrs to watts |
#25
IP: 107.0.6.242
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Thanks for that, Tac - I especially like that small engine mode feature. The 614 seems to be able to deliver what I need (but my requirements are about double yours). Now to come up with the scratch...
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Wrsteinesq (09-19-2016) |
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