Running electric motors with an inverter

[N7RX]

I tried to run a couple of Taco 005 circulator pumps from a 12 VDC battery
and a dime-store (e.g., Walmart) inverter and couldn't do it - the pumps
hummed or buzzed or something but never seemed to run as smoothly as they
do when plugged into the house's AC system. The pumps are 1/25th HP with a
.5 amp rating and I would have thought that they'd run fine on the inverter.
I tried two different invertors, both of which work fine otherwise and also
tried
running one pump at a time. The invertors are rated at 400 and 700 watts.

What's going wrong and how can I fix it? The objective is to be able to run
the pumps from lead-acid batteries as part of a wind/solar powered system.
Are the inverters that are usually spec'd for solar systems, like
Xantrex/Trace, able to run motors?

[George Ghio]

Post by N7RX
I tried to run a couple of Taco 005 circulator pumps from a 12 VDC battery
and a dime-store (e.g., Walmart) inverter and couldn't do it - the pumps
hummed or buzzed or something but never seemed to run as smoothly as they
do when plugged into the house's AC system. The pumps are 1/25th HP with a
.5 amp rating and I would have thought that they'd run fine on the inverter.
I tried two different invertors, both of which work fine otherwise and also
tried
running one pump at a time. The invertors are rated at 400 and 700 watts.
What's going wrong and how can I fix it? The objective is to be able to run
the pumps from lead-acid batteries as part of a wind/solar powered system.
Are the inverters that are usually spec'd for solar systems, like
Xantrex/Trace, able to run motors?

Most likely not enough surge capacity to start a pump.

Did you try the pump dry. Pumps start underload.

[Ron Rosenfeld]

Post by N7RX
I tried to run a couple of Taco 005 circulator pumps from a 12 VDC battery
and a dime-store (e.g., Walmart) inverter and couldn't do it - the pumps
hummed or buzzed or something but never seemed to run as smoothly as they
do when plugged into the house's AC system. The pumps are 1/25th HP with a
.5 amp rating and I would have thought that they'd run fine on the inverter.
I tried two different invertors, both of which work fine otherwise and also
tried
running one pump at a time. The invertors are rated at 400 and 700 watts.
What's going wrong and how can I fix it? The objective is to be able to run
the pumps from lead-acid batteries as part of a wind/solar powered system.
Are the inverters that are usually spec'd for solar systems, like
Xantrex/Trace, able to run motors?

I believe those motors do not like the square wave output from the
inexpensive inverters. They will run, but will be less efficient (and run
hotter). I do not know if this will harm them in the long run.

We have a forced hot water heating system and, I think, five of those
circulating pumps. They all seem to run smoothly powered from my SW5548's,
which has a "pseudo-sine-wave" output.


-- ron (off the grid in Downeast Maine)

[ptaylor]

Post by Ron Rosenfeld

Post by N7RX
I tried to run a couple of Taco 005 circulator pumps from a 12 VDC battery
and a dime-store (e.g., Walmart) inverter and couldn't do it - the pumps
hummed or buzzed or something but never seemed to run as smoothly as they
do when plugged into the house's AC system. The pumps are 1/25th HP with a
.5 amp rating and I would have thought that they'd run fine on the inverter.
I tried two different invertors, both of which work fine otherwise and also
tried
running one pump at a time. The invertors are rated at 400 and 700 watts.
What's going wrong and how can I fix it? The objective is to be able to run
the pumps from lead-acid batteries as part of a wind/solar powered system.
Are the inverters that are usually spec'd for solar systems, like
Xantrex/Trace, able to run motors?

I believe those motors do not like the square wave output from the
inexpensive inverters. They will run, but will be less efficient (and run
hotter). I do not know if this will harm them in the long run.
We have a forced hot water heating system and, I think, five of those
circulating pumps. They all seem to run smoothly powered from my SW5548's,
which has a "pseudo-sine-wave" output.
-- ron (off the grid in Downeast Maine)

I ran my Dremel tool off of my cheap 300W inverter once,it worked
alright,but it was making noises like the bearings were going out,and
coming loose inside the case! grinding/buzzing/rattling noises..
It still works just dandy on mains power,and I don't intend to try it
again on any square wave inverters!
Motors really don't like the harmonic prone square wave inverters..

[N7RX]

Actually, the inverters purportedly are modified sine-wave (aka modified
square wave).

Post by ptaylor

Post by Ron Rosenfeld

Post by N7RX
I tried to run a couple of Taco 005 circulator pumps from a 12 VDC battery
and a dime-store (e.g., Walmart) inverter and couldn't do it - the pumps
hummed or buzzed or something but never seemed to run as smoothly as they
do when plugged into the house's AC system. The pumps are 1/25th HP with a
.5 amp rating and I would have thought that they'd run fine on the inverter.
I tried two different invertors, both of which work fine otherwise and also
tried
running one pump at a time. The invertors are rated at 400 and 700 watts.
What's going wrong and how can I fix it? The objective is to be able to run
the pumps from lead-acid batteries as part of a wind/solar powered system.
Are the inverters that are usually spec'd for solar systems, like
Xantrex/Trace, able to run motors?

I believe those motors do not like the square wave output from the
inexpensive inverters. They will run, but will be less efficient (and run
hotter). I do not know if this will harm them in the long run.
We have a forced hot water heating system and, I think, five of those
circulating pumps. They all seem to run smoothly powered from my SW5548's,
which has a "pseudo-sine-wave" output.
-- ron (off the grid in Downeast Maine)

I ran my Dremel tool off of my cheap 300W inverter once,it worked
alright,but it was making noises like the bearings were going out,and
coming loose inside the case! grinding/buzzing/rattling noises..
It still works just dandy on mains power,and I don't intend to try it
again on any square wave inverters!
Motors really don't like the harmonic prone square wave inverters..

[Ron Rosenfeld]

Post by N7RX
Actually, the inverters purportedly are modified sine-wave (aka modified
square wave).

I would guess that the output looks only marginally like a sine wave, but
I'm not familiar with them.

From your initial post, I got the impression that the motors were running,
but were noisy. Other's seem to feel there is a startup surge issue.

You've also first wrote that the motors were 0.5A motors, and later wrote
they were 0.7A motors. Is there a locked rotor amp rating on these pumps?

The pumps I have are TACO 007-F5. The nameplate indicates 1/25 hp and
0.7A/120V. A capacitor is included -- probably to reduce the startup
surge. And, as I said, they run fine on my SW inverters.

Oh, someone asked if you had started the pump dry. According to the
printed information on the pump, which I just reviewed, and which states it
applies to the "00" cartridges (so I presume it applies to your 005 as well
as my 007), they should never be run dry. The directions state to take
special care that there is water in the system before starting them up.


-- ron (off the grid in Downeast Maine)

[N7RX]

You caught me. I have one 005 and one 007.

Come to think of it, maybe I should run this problem by Q Division.

Post by Ron Rosenfeld

Post by N7RX
Actually, the inverters purportedly are modified sine-wave (aka modified
square wave).

I would guess that the output looks only marginally like a sine wave, but
I'm not familiar with them.
From your initial post, I got the impression that the motors were running,
but were noisy. Other's seem to feel there is a startup surge issue.
they were 0.7A motors. Is there a locked rotor amp rating on these pumps?
The pumps I have are TACO 007-F5. The nameplate indicates 1/25 hp and
0.7A/120V. A capacitor is included -- probably to reduce the startup
surge. And, as I said, they run fine on my SW inverters.
Oh, someone asked if you had started the pump dry. According to the
printed information on the pump, which I just reviewed, and which states it
applies to the "00" cartridges (so I presume it applies to your 005 as well
as my 007), they should never be run dry. The directions state to take
special care that there is water in the system before starting them up.
-- ron (off the grid in Downeast Maine)

[Ron Rosenfeld]

Post by N7RX
You caught me. I have one 005 and one 007.
Come to think of it, maybe I should run this problem by Q Division.

Well, are they running, but noisy, as I surmised; or not even starting as
others have indicated?


-- ron (off the grid in Downeast Maine)

[s***@yahoo.com]

Post by Ron Rosenfeld
We have a forced hot water heating system and, I think, five of those
circulating pumps. They all seem to run smoothly powered from my
SW5548's, which has a "pseudo-sine-wave" output.

The SW series are sine wive with some 50 or 60 steps, which to almost
anything looks like a sine wave.

I wouldnt wish anyone to think pseudo-sine-wave in any way relates to
modified sine wave which is actually a bastardized square wave.

There are probably several problems in the original poster's post, not just
one.

1. May need a surge current more than your inverter can handle
2. May need a sine wave

The moral of the story is......

U S E S I N E W A V E I N V E R T E R S
AND
F O R G E T M O D I F I E D S I N E W A V E (i e s q u a r e w
a v e b a s t a r d i z e d)

Simon

[Luc Collin]

You just nailed the problem with a 'transformerless' inverter. There is not
places to store enough energy to sustain the current spike needed to start a
motor. The humming you hear is the same as the humming of a ceiling fan when
it starts (but the fan uses capacitor start).

For your system you need to check with the motor manufacturer what the
starting current is, and with the inverter company what is their surge
capability is. Starting current of a motor can be as much a 8 times larger
than its operating current.

If I was in your shoes, once I was convinced that I needed another inverter,
I would probably try to find a 1kVA AC isolation tranformer and see if that
could store energy. Be aware that frying your inverter IS POSSIBLE with this
trick . Also possible to overheat the transformer with a square wave
inverter. This is very much a hit and miss solution.


Good Luck,

-Luc

Post by N7RX
I tried to run a couple of Taco 005 circulator pumps from a 12 VDC battery
and a dime-store (e.g., Walmart) inverter and couldn't do it - the pumps
hummed or buzzed or something but never seemed to run as smoothly as they
do when plugged into the house's AC system. The pumps are 1/25th HP with a
.5 amp rating and I would have thought that they'd run fine on the inverter.
I tried two different invertors, both of which work fine otherwise and also
tried
running one pump at a time. The invertors are rated at 400 and 700 watts.
What's going wrong and how can I fix it? The objective is to be able to run
the pumps from lead-acid batteries as part of a wind/solar powered system.
Are the inverters that are usually spec'd for solar systems, like
Xantrex/Trace, able to run motors?

[N7RX]

It's also been suggested that I put a large capacitor across the AC line
input to help kick start the motors but no suggestion as to how large.
Wouldn't
this do the same as a transformer?

The starting current seems like the most likely culprit and I've read that
starting current can be as much as 15 times the motor rating. The motors are
about .7 amps, which would make the starting current about 11 amps. If the
inverter is rated for 700 watts it does have quite enough oomph to start the
motors.

Post by Luc Collin
You just nailed the problem with a 'transformerless' inverter. There is not
places to store enough energy to sustain the current spike needed to start a
motor. The humming you hear is the same as the humming of a ceiling fan when
it starts (but the fan uses capacitor start).
For your system you need to check with the motor manufacturer what the
starting current is, and with the inverter company what is their surge
capability is. Starting current of a motor can be as much a 8 times larger
than its operating current.
If I was in your shoes, once I was convinced that I needed another inverter,
I would probably try to find a 1kVA AC isolation tranformer and see if that
could store energy. Be aware that frying your inverter IS POSSIBLE with this
trick . Also possible to overheat the transformer with a square wave
inverter. This is very much a hit and miss solution.
Good Luck,
-Luc

Post by N7RX
I tried to run a couple of Taco 005 circulator pumps from a 12 VDC battery
and a dime-store (e.g., Walmart) inverter and couldn't do it - the pumps
hummed or buzzed or something but never seemed to run as smoothly as they
do when plugged into the house's AC system. The pumps are 1/25th HP with a
.5 amp rating and I would have thought that they'd run fine on the

inverter.

Post by N7RX
I tried two different invertors, both of which work fine otherwise and

also

Post by N7RX
tried
running one pump at a time. The invertors are rated at 400 and 700 watts.
What's going wrong and how can I fix it? The objective is to be able to

run

Post by N7RX
the pumps from lead-acid batteries as part of a wind/solar powered

system.

Post by N7RX
Are the inverters that are usually spec'd for solar systems, like
Xantrex/Trace, able to run motors?

[Luc Collin]

A large capacitor usually refers to an electrolytic capacitor. I would avoid
to put one across an AC line because it is polarized. A electrolytic caps
can go off like shotgun shell if reverse biased. Unpolorized caps are not
usually much bigger than a few uF, so I guess large can be relative.

Maybe the person was suggesting a capacitor start for a single phase motor,
where the capacitor is not used to store energy, but to shift the current
curve vs. voltage. This will keep the two forces to cancel each other out (I
don't want to get into motor theory). This scheme is commonly used with
ceiling fans.

So, IMO, you problem will still be the same, you do not have enough energy
stored anywhere to sustain the spike. The only thing the capacitor has done
is shift the current spike with respect to voltage. I am not 100% sure, but
I don't think that a capacitor start will help you out. On the other hand,
capacitors are cheap may be worth trying. Make sure you don't use a
polorized cap without a shield and goggles. We do not need another capacitor
related death in the US. :-)


-Luc

Post by N7RX
It's also been suggested that I put a large capacitor across the AC line
input to help kick start the motors but no suggestion as to how large.
Wouldn't
this do the same as a transformer?
The starting current seems like the most likely culprit and I've read that
starting current can be as much as 15 times the motor rating. The motors are
about .7 amps, which would make the starting current about 11 amps. If the
inverter is rated for 700 watts it does have quite enough oomph to start the
motors.

Post by Luc Collin
You just nailed the problem with a 'transformerless' inverter. There is

not

Post by Luc Collin
places to store enough energy to sustain the current spike needed to

start

Post by N7RX
a

Post by Luc Collin
motor. The humming you hear is the same as the humming of a ceiling fan

when

Post by Luc Collin
it starts (but the fan uses capacitor start).
For your system you need to check with the motor manufacturer what the
starting current is, and with the inverter company what is their surge
capability is. Starting current of a motor can be as much a 8 times larger
than its operating current.
If I was in your shoes, once I was convinced that I needed another

inverter,

Post by Luc Collin
I would probably try to find a 1kVA AC isolation tranformer and see if

that

Post by Luc Collin
could store energy. Be aware that frying your inverter IS POSSIBLE with

this

Post by Luc Collin
trick . Also possible to overheat the transformer with a square wave
inverter. This is very much a hit and miss solution.
Good Luck,
-Luc

Post by N7RX
I tried to run a couple of Taco 005 circulator pumps from a 12 VDC

battery

Post by Luc Collin

Post by N7RX
and a dime-store (e.g., Walmart) inverter and couldn't do it - the pumps
hummed or buzzed or something but never seemed to run as smoothly as

they

Post by Luc Collin

Post by N7RX
do when plugged into the house's AC system. The pumps are 1/25th HP

with

Post by N7RX
a

Post by Luc Collin

Post by N7RX
.5 amp rating and I would have thought that they'd run fine on the

inverter.

Post by N7RX
I tried two different invertors, both of which work fine otherwise and

also

Post by N7RX
tried
running one pump at a time. The invertors are rated at 400 and 700

watts.

Post by Luc Collin

Post by N7RX
What's going wrong and how can I fix it? The objective is to be able to

run

Post by N7RX
the pumps from lead-acid batteries as part of a wind/solar powered

system.

Post by N7RX
Are the inverters that are usually spec'd for solar systems, like
Xantrex/Trace, able to run motors?

[Ron Rosenfeld]

Post by Luc Collin
A large capacitor usually refers to an electrolytic capacitor. I would avoid
to put one across an AC line because it is polarized. A electrolytic caps
can go off like shotgun shell if reverse biased. Unpolorized caps are not
usually much bigger than a few uF, so I guess large can be relative.
Maybe the person was suggesting a capacitor start for a single phase motor,
where the capacitor is not used to store energy, but to shift the current
curve vs. voltage. This will keep the two forces to cancel each other out (I
don't want to get into motor theory). This scheme is commonly used with
ceiling fans.
So, IMO, you problem will still be the same, you do not have enough energy
stored anywhere to sustain the spike. The only thing the capacitor has done
is shift the current spike with respect to voltage. I am not 100% sure, but
I don't think that a capacitor start will help you out. On the other hand,
capacitors are cheap may be worth trying. Make sure you don't use a
polorized cap without a shield and goggles. We do not need another capacitor
related death in the US. :-)

He has two different model pumps that are closely related 005 and 007. I
have the 007's and they definitely have a capacitor in the circuit. It's
been three years since I looked at it closely so I don't recall the
details, but I was reviewing the sheet on the motor the other day, and they
do talk about replacing it if necessary (but the sheet does not give a spec
on it).

I would assume the 005 also has a capacitor.

Post by Luc Collin
-Luc

Post by N7RX
It's also been suggested that I put a large capacitor across the AC line
input to help kick start the motors but no suggestion as to how large.
Wouldn't
this do the same as a transformer?
The starting current seems like the most likely culprit and I've read that
starting current can be as much as 15 times the motor rating. The motors

are

Post by N7RX
about .7 amps, which would make the starting current about 11 amps. If the
inverter is rated for 700 watts it does have quite enough oomph to start

the

Post by N7RX
motors.

Post by Luc Collin
You just nailed the problem with a 'transformerless' inverter. There is

not

Post by Luc Collin
places to store enough energy to sustain the current spike needed to

start

Post by N7RX
a

Post by Luc Collin
motor. The humming you hear is the same as the humming of a ceiling fan

when

Post by Luc Collin
it starts (but the fan uses capacitor start).
For your system you need to check with the motor manufacturer what the
starting current is, and with the inverter company what is their surge
capability is. Starting current of a motor can be as much a 8 times

larger

Post by N7RX

Post by Luc Collin
than its operating current.
If I was in your shoes, once I was convinced that I needed another

inverter,

Post by Luc Collin
I would probably try to find a 1kVA AC isolation tranformer and see if

that

Post by Luc Collin
could store energy. Be aware that frying your inverter IS POSSIBLE with

this

Post by Luc Collin
trick . Also possible to overheat the transformer with a square wave
inverter. This is very much a hit and miss solution.
Good Luck,
-Luc

Post by N7RX
I tried to run a couple of Taco 005 circulator pumps from a 12 VDC

battery

Post by Luc Collin

Post by N7RX
and a dime-store (e.g., Walmart) inverter and couldn't do it - the

pumps

Post by N7RX

Post by Luc Collin

Post by N7RX
hummed or buzzed or something but never seemed to run as smoothly as

they

Post by Luc Collin

Post by N7RX
do when plugged into the house's AC system. The pumps are 1/25th HP

with

Post by N7RX
a

Post by Luc Collin

Post by N7RX
.5 amp rating and I would have thought that they'd run fine on the

inverter.

Post by N7RX
I tried two different invertors, both of which work fine otherwise and

also

Post by N7RX
tried
running one pump at a time. The invertors are rated at 400 and 700

watts.

Post by Luc Collin

Post by N7RX
What's going wrong and how can I fix it? The objective is to be able

to

Post by N7RX

Post by Luc Collin
run

Post by N7RX
the pumps from lead-acid batteries as part of a wind/solar powered

system.

Post by N7RX
Are the inverters that are usually spec'd for solar systems, like
Xantrex/Trace, able to run motors?

-- ron (off the grid in Downeast Maine)

[n***@ece.villanova.edu]

Post by Luc Collin
You just nailed the problem with a 'transformerless' inverter. There is not
places to store enough energy to sustain the current spike needed to start a
motor...

Transformers store energy?

Nick

[andy]

All inverters have transformers. The cheapo light-weight versions
probably contain a high-frequency transformer in a DC-DC converter
section to convert the 12V to about 150VDC. In fact the cheapo HF
inverters often contain more energy storage on the DC bus link than
the bulky single stage LF heavy transformer based inverters. I think
the surge capabilities of the LF designs are due to a higher thermal
mass and longer time constant before everything overheats than
anything else. I think it has little to do with energy storage
capabilities.

In any case sine wave inverters will run motors better but it may not
matter that much. If the motors don't get too hot and their power
draw is not excessive (like 1.5x) then don't sweat it. They have a
three year warranty!

Andy

Post by n***@ece.villanova.edu

Post by Luc Collin
You just nailed the problem with a 'transformerless' inverter. There is not
places to store enough energy to sustain the current spike needed to start a
motor...

Transformers store energy?
Nick

[n***@ece.villanova.edu]

I'd like to make a standalone non-freezing horse-waterer with Brinkman's
$60 PV motion sensing yard light (or Steve Spence's better version) and
a 6 VDC submersible pump that moves about 1 gpm up from the bottom of a
55 gallon drum into a bucket on top that slowly drains back into the drum.
Anyone know of a suitable pump?

Nick

[n***@ece.villanova.edu]

Post by n***@ece.villanova.edu
I'd like to make a standalone non-freezing horse-waterer with Brinkman's
$60 PV motion sensing yard light (or Steve Spence's better version) and
a 6 VDC submersible pump that moves about 1 gpm up from the bottom of a
55 gallon drum into a bucket on top that slowly drains back into the drum.
Anyone know of a suitable pump?

Or a 12 V PV motion detector light and a 12 V pump?

Nick

[Bill Kaszeta / Photovoltaic Resources]

http://www.allelectronics.com
search on pump

Post by n***@ece.villanova.edu
I'd like to make a standalone non-freezing horse-waterer with Brinkman's
$60 PV motion sensing yard light (or Steve Spence's better version) and
a 6 VDC submersible pump that moves about 1 gpm up from the bottom of a
55 gallon drum into a bucket on top that slowly drains back into the drum.
Anyone know of a suitable pump?
Nick

Bill Kaszeta
Photovoltaic Resources Int'l
Tempe Arizona USA
***@kaszeta.org

[n***@ece.villanova.edu]

Post by Bill Kaszeta / Photovoltaic Resources
http://www.allelectronics.com
search on pump

Thanks Bill. Nice price. I'm still looking for 1) a 6 V submersible pump or
2) a 12 V PV motion detector light and a 12 V submersible pump. Pump and hose
freeze protection and animal safety seem easier with a submersible pump. Hmm.
The tubing may develop an ice plug where it goes through the ice near the top
of the drum. Maybe the wires should go through the tubing. Would Attwood's
V1250 bilge pump move 1 gpm with a 3' head at 6 volts?

Post by Bill Kaszeta / Photovoltaic Resources

Post by n***@ece.villanova.edu
I'd like to make a standalone non-freezing horse-waterer with Brinkman's
$60 PV motion sensing yard light (or Steve Spence's better version) and
a 6 VDC submersible pump that moves about 1 gpm up from the bottom of a
55 gallon drum into a bucket on top that slowly drains back into the drum.
Anyone know of a suitable pump?

Nick

[Luc Collin]

In some application you can use them to store energy, best example is a
flyback power supply. (where a forward power supply will just transfer
energy and will need an extra inductor on its output). This application is
similar but at different scale.

If you have inductance, you are storing energy.

I am sure that this discussion is bound to be rehashed when the flurry of
new grid tied inverter will be out this summer. Where the new trend seems to
be with small transformers and also super light weight.

-Luc

Post by n***@ece.villanova.edu

Post by Luc Collin
You just nailed the problem with a 'transformerless' inverter. There is not
places to store enough energy to sustain the current spike needed to start a
motor...

Transformers store energy?
Nick