Vermonter Posted November 17, 2009 Report Posted November 17, 2009 Hello all... so, I recently ordered a new pump motor online, and the specs they had listed on the web site do not match the specs on the motor, now that I have received it. It turns out I only needed a 4 HP motor, and, as according to the specs listed on the web site, I ordered a 5 HP motor. My question is: can I use it anyway? It seems to me that by the time I ship it back to them (although I suppose I could get them to pay the return shipping) it wouldn't be worth it (plus the additional time w/o my tub!)... the SF amps on the installed motor are 16.4/4.8; the SF amps on the one I received are 19.5/5.0. Thanks in advance. Tony Quote
hot_water Posted November 17, 2009 Report Posted November 17, 2009 Hello all... so, I recently ordered a new pump motor online, and the specs they had listed on the web site do not match the specs on the motor, now that I have received it. It turns out I only needed a 4 HP motor, and, as according to the specs listed on the web site, I ordered a 5 HP motor. My question is: can I use it anyway? It seems to me that by the time I ship it back to them (although I suppose I could get them to pay the return shipping) it wouldn't be worth it (plus the additional time w/o my tub!)... the SF amps on the installed motor are 16.4/4.8; the SF amps on the one I received are 19.5/5.0. Thanks in advance. Tony Tony, your best bet is to talk to the manufacturer on this. Under normal operation I wouldn't expect the 5 hp motor to draw much more than the old 4 hp motor did, since the load on the motor is determined by the pump. In other words, a 2-pole AC induction motor is going to run at "about" 3450 rpm, and the torque it needs to produce to spin the pump that fast (which is related to the current draw) is mostly a function of the pump, not the motor. But the fact is that there are conditions where that motor could draw significantly more current than the old one, and this can get you in trouble. For example, the startup current of the larger motor will be higher than that of the old motor. This shouldn't exceed the relay's specs.... the spa manufacturer should know if it'll be a problem. There's other annoying things that *could* happen as well, unlikely perhaps.... but still I would probably talk to the spa's designers before installing that motor. Quote
quantumchromodynamics Posted November 17, 2009 Report Posted November 17, 2009 Deleted post. I had missed a detail in the post that makes my original reply unnecessary. Quote
Vermonter Posted November 17, 2009 Author Report Posted November 17, 2009 Hello all... so, I recently ordered a new pump motor online, and the specs they had listed on the web site do not match the specs on the motor, now that I have received it. It turns out I only needed a 4 HP motor, and, as according to the specs listed on the web site, I ordered a 5 HP motor. My question is: can I use it anyway? It seems to me that by the time I ship it back to them (although I suppose I could get them to pay the return shipping) it wouldn't be worth it (plus the additional time w/o my tub!)... the SF amps on the installed motor are 16.4/4.8; the SF amps on the one I received are 19.5/5.0. Thanks in advance. Tony Tony, your best bet is to talk to the manufacturer on this. Under normal operation I wouldn't expect the 5 hp motor to draw much more than the old 4 hp motor did, since the load on the motor is determined by the pump. In other words, a 2-pole AC induction motor is going to run at "about" 3450 rpm, and the torque it needs to produce to spin the pump that fast (which is related to the current draw) is mostly a function of the pump, not the motor. But the fact is that there are conditions where that motor could draw significantly more current than the old one, and this can get you in trouble. For example, the startup current of the larger motor will be higher than that of the old motor. This shouldn't exceed the relay's specs.... the spa manufacturer should know if it'll be a problem. There's other annoying things that *could* happen as well, unlikely perhaps.... but still I would probably talk to the spa's designers before installing that motor. Well, sadly, the manufacturer went out of business, and the company that took over their spa parts division is pretty well useless. The motor is rated at 3450/1750 rpm's, the same as the old one, if that makes a difference. Hmm... maybe I should just send the thing back and get the right one?? Thanks for the input! Quote
reeffreak Posted November 17, 2009 Report Posted November 17, 2009 Perhaps you could post some specifics on the control pack, and one of the techs on the board could tell you whether the board can handle the load. Quote
Pool Clown Posted November 18, 2009 Report Posted November 18, 2009 Check the relay that switches the pump in question. It may have a Hp/Amp rating on the relay itself. That and make sure that your breaker, (service to the tub) will handle the increased amps without tripping when switched to high. Quote
Vermonter Posted November 18, 2009 Author Report Posted November 18, 2009 reeffreak, what specifically do I need to know about the control pack? And where do I find this info? (In the manual? On the tub?) Pool Clown, what/where are the relay switches on/for the pump? Please bear with me guys, new at this stuff. The breaker for the tub (the one in the fuse box) is 50 amps, so that shouldn't be a problem. I never use the blower- ever- but even so, I can't imagine that would use up the additional 25+ amps. Thanks for the help- Tony Quote
quantumchromodynamics Posted November 18, 2009 Report Posted November 18, 2009 The breaker for the tub (the one in the fuse box) is 50 amps, so that shouldn't be a problem. I never use the blower- ever- but even so, I can't imagine that would use up the additional 25+ amps. If it's not too much trouble, I think that you would do best with an exact match to your old motor. How much time and money would that cost you? Perhaps you could send the motor back and get a new one locally from an electric motor shop. How many amps does the heater use? Quote
hot_water Posted November 18, 2009 Report Posted November 18, 2009 Hello all... so, I recently ordered a new pump motor online, and the specs they had listed on the web site do not match the specs on the motor, now that I have received it. It turns out I only needed a 4 HP motor, and, as according to the specs listed on the web site, I ordered a 5 HP motor. My question is: can I use it anyway? It seems to me that by the time I ship it back to them (although I suppose I could get them to pay the return shipping) it wouldn't be worth it (plus the additional time w/o my tub!)... the SF amps on the installed motor are 16.4/4.8; the SF amps on the one I received are 19.5/5.0. Thanks in advance. Tony Tony, your best bet is to talk to the manufacturer on this. Under normal operation I wouldn't expect the 5 hp motor to draw much more than the old 4 hp motor did, since the load on the motor is determined by the pump. In other words, a 2-pole AC induction motor is going to run at "about" 3450 rpm, and the torque it needs to produce to spin the pump that fast (which is related to the current draw) is mostly a function of the pump, not the motor. But the fact is that there are conditions where that motor could draw significantly more current than the old one, and this can get you in trouble. For example, the startup current of the larger motor will be higher than that of the old motor. This shouldn't exceed the relay's specs.... the spa manufacturer should know if it'll be a problem. There's other annoying things that *could* happen as well, unlikely perhaps.... but still I would probably talk to the spa's designers before installing that motor. Well, sadly, the manufacturer went out of business, and the company that took over their spa parts division is pretty well useless. The motor is rated at 3450/1750 rpm's, the same as the old one, if that makes a difference. Hmm... maybe I should just send the thing back and get the right one?? Thanks for the input! Two-speed motors are basically all 3450/1750, so no, it doesn't really play into your question. The relay may be marked - but be aware that the SF amps are not the same thing as the startup amps. That aside, any time you put more current through a relay, you shorten its life. So other than the convenience of not returning your motor, there's not a lot of upside that I see by using this motor. The pump won't really run any better, since 3450 rpm is as fast as it will turn. Also, to do the job right, you would need to ensure that the wire guage from the controller to the motor is adequate, and there's also an outside chance that you might start popping your breaker on pump startup, due to momentary high startup current. Unless you're pretty comfortable with figuring all this stuff out - or willing to take a chance - it's probably a better idea in the long run to just exchange the motor for the correct size, and get back to enjoying your tub. Quote
Vermonter Posted November 19, 2009 Author Report Posted November 19, 2009 Okay, thanks for the advice... I ordered the right motor and will just return the one I have. I suppose in the end it may end up costing me an additional $25 or so, not that big a deal. Thanks for leading me in the right direction. Tony Quote
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