Help determining what NEMA starter is needed

[Sean Kinn]

All, I was hoping I could pick your brains, as I have become rather confused about what is required. Here's the facts:

The tool: Vintage Unisaw
The Motor: Baldor WWL3606 3hp 230v single phase, 15.5FLA, 5.x no load amps.
The current starter (that I already had when the 1hp bullet motor was installed): Square D NEMA size 00, 240v coil, with heaters rated at about 9FLA if I am remembering correctly.

Current status: I did a lot of research on various sites that led me to believe my current NEMA size 00 starter was not appropriate and that I needed a new Size 0 or Size 1 starter with the appropriate heaters. However, in my excitement I wanted to give the new Baldor a test run so I decided to give it a go with my current starter (figuring the worst that would happen is I would trigger the overload). Well I started and stopped the saw probaby 20 times, and made several test cuts in 4/4 white oak and she just kept humming along.

The question: Am I just asking for trouble running this with the size 00 starter? This is one of the Square D units that are way overbuilt, and retailed for $300+ when new, not one of the low dollar modern asian specials. This saw is used in a hobby shop setting for only an hour or so per week at the most. I'm fine with spending the money on a new (used) starter and the required heaters, but I find myself wondering if it is truly required.

Thoughts?

[Kevin Presutti]

Sean see if this helps you http://eatonsliderule.com/free_horsepower_single.aspx . It looks to me like you will need a size 1. I'm not an electrician but I have done a few projects and I prefer to Eaton as a resource. Best of luck!

[David Kumm]

Generally a starter with 15 amp heaters is a size one. At the top end of size 0. Square D uses the same size enclosure for both. Assuming a magnetic starter although many saws just use a manual one. Make sure the heaters are sized properly. Some starters have adjustable ones although i prefer the regular ones. Dave

[Van Huskey]

I am interested in the answers since starters are one of the things I need to learn more about. It would seem too small a heater could lead to thermal shutoffs well within the safe range of a motor and MAYBE with if the contactors are too small they could weld or worse. The chart I have used in the past says size 1 for your motor.

Again, I would defer to those that know more than I!

[Van Huskey]

Generally a starter with 15 amp heaters is a size one. At the top end of size 0. Square D uses the same size enclosure for both. Assuming a magnetic starter although many saws just use a manual one. Make sure the heaters are sized properly. Some starters have adjustable ones although i prefer the regular ones. Dave

Do any of the "good" starters have adjustable heaters or is it just the new cheapy versions, I was under the impression it was the latter.

[David Kumm]

Van, some of the older Sq D similar to the 8536 had them. My favorite old starters are the CH 9586, and AB 709- both magnetic and the AB 609 manual. I forget some of the others I have. The AB 509 are newer but much deeper front to back so I don't like the look as much. If you come up I'll show you my inventory. Dave

[Van Huskey]

Van, some of the older Sq D similar to the 8536 had them. My favorite old starters are the CH 9586, and AB 709- both magnetic and the AB 609 manual. I forget some of the others I have. The AB 509 are newer but much deeper front to back so I don't like the look as much. If you come up I'll show you my inventory. Dave

I look forward to it.

In the past I have just either fixed the issue with the check wrench (IE this is what I have, sell me what I need) or in the case of three phase VFDed my way around it. I plan to change the motor on my Delta BS and have a 3ph motor that I planned to VFD but now if "the plan" comes together and I have to get a RPC I will just put a 3ph starter on it. This thing has seemingly enough electrical stuff in it to run a small towns substation and some kinda goofy motor brake that half works and makes the thing rumble to a stop like a concrete truck with a flat tire. It has a simple manual "art deco" on/off switch that I hope to be able to keep. It was a school saw and I assume bodged over the years with what ever was available. Anyway I figure this is a subject every man should understand and I just don't.

[Kevin Presutti]

Check out Eaton's calculator http://emsco.net/starter-sizing.htm . It is pretty self explanitory.

[Sean Kinn]

Thanks all. What I didn't mention in my first post is that I also have a Square D NEMA size 0 starter that I could use that I obtained via a previous tool deal. Another source of my confusuion is that the charts that Kevin linked to above seem to conflict with the label on my Size 0 starter. My Square D NEMA Size 0 starter clearly says 3HP right on the label. Am I missing something....maybe that's for three phase? Beyond the heaters (that you can swap out), and the magnetic coil voltage, I'd really like to know what is functionally different between say a Size 00, a Size 0, and a Size 1. I'm still only talking about 230v and 15 amps here, and in a home use setting not an all-day every day idustrial one. Heck, I had previous 115v 1.5hp tools that claimed 15 amps at full load that were controlled by incredibly poorly made non-magnetic push-button start/stop switches (that came that way from the factory).

I want to use the starter and heaters that are required for my new 3hp Baldor, but I'm just struggling to understand the differences beyond simply looking at the chart and following it as the letter of the law. Would I be fine using my Size 0 starter with the appropriate heaters for my limited hobby use? For those of you that have not priced out these starters (and heaters) the cost can add up quickly, so that's why I am trying to determine if it is possible to utilize the starters I already have before investing another $50-$125 or so for quality used Square D components.

[David Kumm]

You want to use the chart inside the enclosure, assuming the guts are what is labeled on the sheet. The same heater will be rated differently on different size starters. If the sheet says you can use 15+ amp heaters you are good to go for your application. Generally you want the starter sized so the heaters are not at the top end but for hobby use you will be fine. Very seldom you will be fully loading the motor. SQ D starters are expensive even used, hence my preference for the 709. Much cheaper. Dave

[Rod Sheridan]

As the starter size increase the following changes

- full load current rating (thermal)

- Locked rotor current rating (depends upon HP and Nema design letter for the motor. Contacts have to resist welding under the 6 to 10 times full load current)

- interrupting rating, contacts and mechanical assemblies must withstand the arcing and mechanical forces during faults.

So yes a 3 HP single phase motor, 240 volts AC would need a size 1 starter..............Rod.

[Kirk Poore]

Sean:

The label inside the enclosure or a label on the starter will usually state ratings for both single and three phase. If there is only one rating, and it's a 3ph starter, assume it's the 3ph rating. I think you're going to need a size 1. And yes, you're risking problems if your starter is the wrong size. I smoked a size 0 starter by running it on a 5 hp/3ph motor continuously for about an hour, even though the heaters were the right size for the current draw.

I've bought used, good condition Square D 8536's on fleabay for $30 more than once, and used heaters cost me $6-12 each depending on source.

Kirk

[Don Jarvie]

You need a Size 1 starter for 3hp 1ph because the of the amp draw. Even though a Size 00 or Size 0 will work it will overheat the coil and will fail. If the motor has overload protection like a reset on it you don't need the heaters just the magnetic starter. If you fo get the heaters they need to be rated for the amp draw.

Go to the Square D website and you should be able to find the same type of starter you have but in Size 1. You can also look at what size heaters it will require. The heaters and starters go according to the amount of amps the motor draws. Once you get the right model number you can search Ebay and find one. I did this for my PM 66 when I replaced the motor and need to upgrade the starter. I bought the Size 1 equivalent Furnas brand since I had the enclosure.

That being said I used a light switch type rated for 30 amps on my old table saw since my motor had overload protection on it for years with no issue.

[Sean Kinn]

Thanks again everyone! I will be selling my current size 00 and size 0 to fund a size 1 with the proper heaters. I appreciate all of your input! I think one of the biggest things that had thrown me off were the ratings for three-phase versus single phase.

[Don Jarvie]

I would keep them if you don't need the funds to buy the new one. These might come in handy if you buy and older tool and you need a starter.