Motors and Variable Frequency Drives

There are many different options and recommendations on what motors and VFD’s to use on a 2×72 Belt Grinder.  We have put together a simplified version of recommend options to use on the Nexus Grinders.  This by no means are the only options for motors or VFD’s.  Do your research and become informed on what is needed to power and control a 2×72 belt grinder.

The key factor for determining what size motor and/or VFD to use will depend on what power you have available in your shop or garage.
If you only have 115 volt supply, you will be looking at using 1.0 to 1.5 horsepower motors.
If you have 230 volt supply, you will be looking at using 1, 1.5, and 2.0 horsepower motors.  You can go with larger horsepower motors, but you will need a larger rated VFD which will increase costs.

Motors
If you use a 56C frame motor with a foot mount, you can use the C face mount for the NG-3. With the foot mount you can also use it for NG-2 model.  Most motors now days offer both a C face and a foot mount.  If you don’t have one or can’t find one, make sure you obtain the correct motor mount for the Grinder. Nexus Grinders sells motors for the NG-3 and NG-2

You want to use Total Enclosed Fan Cool (TEFC) motors. Open motors are a poor choice, as grinding dust will get inside of the motor and it will eventually fail.
If you are using a 4” or 5″ drive wheel, you will want a 3600 rpm motor.
You should also look for motors that are electronically reversible.
If you are using a VFD, you will need a 3-phase motor. (see VFD notes below).
If you want to use a counter shaft with pillow blocks, sheaves (pulleys) and belt, you can use a 1.5 or 2.0 horsepower, single phase motor. You can only use this type of setup with the NG-2 models.

Variable Frequency Drives
Variable Frequency Drives are commonly referred to VFD’s.
If you want to use a VFD, you need to use a 3-phase motor.
VFD’s convert single phase 115 or 230 volt inputs into 3-phase outputs to the motor.
You can’t use a single-phase motor on the industry standard VFD’s that most knife makers use for grinders.
VFD’s control speed and some may also allow you to use forward and reverse settings.
You can’t use a motor that is rated higher than the VFD rating. You can use a higher rated VFD with a lower rated motor. So you can use a 2.0 horsepower VFD with a 1.0 to 2.0 horsepower 3 phase motors.  You should not use a 3.0 horsepower motor with a 2.0 horsepower rated VFD.

There are many manufactures of VFD’s, so look for a VFD with a NEMA 4-X protection rating which is sealed from dust, water and a corrosion resistant exterior. If you use a VFD with NEMA 1 rating, you will need to protect the drive and provide a fan and filter to keep the drive cool and to not allow grinding dust to penetrate your VFD.  In the end, it’s not much more money and definitely worth your time to buy a NEMA 4-X rated VFD.

KB Electronics sells many models of VFD’s.  You can buy KBAC drives from Nexus Grinders in Canada who is an authorized distributor.

If you purchase the KBAC-27D model, you can use the VFD with the 115 and 230 volt inputs and can use 1.0 horsepower, 1.5 horsepower and 2.0 horse power, 3-phase motors.

The 115 volt input you can use a 1.0 or 1.5 (maximum) horsepower, 3-phase motor.
The 230 volt input you can use a 1.0, 1.5. or 2.0 horsepower, 3-phase motor.

AC line input 115 volts, maximum current 22 amps, and a 25 amp circuit breaker.
AC line input 230 volts, maximum current 16.7 amps, and a 20 amp circuit breaker. Make sure you have the required power supply and circuits available. See Table 2 on page 7 kbac_manual

If you use the KBAC-24D model you are limited to a maximum of 1.0 horsepower, 3-phase motor.
AC line input 115 volts, maximum current is 14.4 amps and a 20 amp circuit breaker. Make sure you have the required power supply and circuit available.

The KBAC VFD’s are rated NEMA 4-X. You can also add an optional forward and reverse switch along with a line switch that will allow you to turn the power off to the drive.

Recommendations:
Now that you have learned a lot about motors and VFD’s. Here are some recommendations we have put together to assist you in making your decision.

Option 1
1.5 horsepower or 2.0 horsepower, 230 volt, 3-phase motor.
56C or 56HC flange Mount
Electronically reversible
TEFC (Total Enclosed Fan Cooled)
3600 rpm (use with 4”or 5″ Drive Wheel)
Variable Frequency Drive (VFD) KBAC 27D 230 volt single-phase input (rated up to 2 hp)

Option 2
1.0 to 1.5 horsepower, 230 volt, 3-phase motor.
56C or 56HC flange Mount
Electronically reversible
TEFC (Total Enclosed Fan Cooled)
3600 rpm (use with 4” or 5″ Drive Wheel)
Variable Frequency Drive (VFD) KBAC 27D 115 volt single-phase input (rated up to 1.5 hp)

Option 3
1.0 horsepower, 230 volt, 3-phase motor.
56C or 56HC flange Mount
Electronically reversible
TEFC (Total Enclosed Fan Cooled)
3600 rpm (use with 4” or 5″ Drive Wheel)
Variable Frequency Drive (VFD) KBAC 24D 115 volt single-phase input (rated up to 1 hp).

Option 4
1.5 horsepower, 115 volt, single-phase motor.
56C or 56HC flange Mount
Electronically reversible
TEFC (Total Enclosed Fan Cooled)
3600 rpm (use with 4” or 5″ Drive Wheel)
Counter-shaft, with pulleys and belt or as a direct motor mount on the NG-3

Nexus Grinders sells 1hp, 1.5hp and 2hp three phase motors for your convenience. We can also obtain single phase motors too.

eMotors Direct is a Canadian Distributor with operations across Canada. Their prices are very competitive and they generally have flat rate shipping on motors.  eMotors Direct  or 1-800-890-7593

For KBAC drives, please review the manual available at KB Electronics. You can also contact Nexus Grinders who is an authorized re-seller for information on KB Electronics VFD’s.   https://www.kbelectronics.com

Warning:
Working on electrical circuits or incorrectly connecting electrical equipment can be extremely hazardous. Please consult with qualified electrician and qualified personnel if you are unsure how to make safe electrical connections.  Electrical connections should meet or exceed National, Provincial, and local electrical codes. Always refer to the manufacture’s manuals and installation instructions. You may need permits if you are making changes or adding circuits to your electrical panel. Please check with your local authorities before starting any electrical connections.

115 volt or 230 volt supply in my shop

Now that you have picked the Nexus grinder you want, you now need to figure out how to power the motor or VFD and motor. Below is some information to assist you in making some decisions based on power available in your garage or shop.

The single biggest factor is what power do you have available in your garage or shop? Most garages generally have limited circuits and most garage setups have 115 volt 15 Amp circuits to power the lights, a few plugs, garage door opener and maybe a central vacuum system. If you have the service panel or a sub-panel located in your garage or shop you will have more options available to you. If your service panel is located in the house, you may have limited access to run a new circuit into your garage.

*Note: the information provided, are only recommendations. You should always consult with a qualified electrician.

230 volt supply with 20 Amp breaker
If you have 230 volt supply in your garage or shop, you can easily run a 2 hp motor and a VFD. All you need is 20 Amp double pole breaker and 12/3 conductor wire from your panel to your VFD and motor. With 230 volts, you can use a KBAC-27D or KBAC-24D and 3 phase motors. If you choose to go with a single speed single phase 230 volt motor, you can run most motors up to 2 hp easily.

115 volt supply with 25 Amp breaker
If you have 115 volt 25 amp circuit in your garage or shop you are a little more limited. Here you can run a KBAC-27D with a 1 hp or 1.5 hp 3 phase motor. With a 115 volt supply, the KBAC-27D VFD draws maximum current of 22 amps and requires a 25 amp circuit breaker and 10/3 conductor wire from the panel to the VFD. You can also run a single speed single phase motors up to 2 hp (check the motor ratings).

115 volt supply with 20 Amp breaker
If you have 115 volt 20 amp circuit in your garage or shop you are a little more limited. Here you can run a KBAC-24D with a 1 hp 3 phase motor. With a 115 volt supply, the KBAC-24D VFD draws maximum current of 14.4 amps and requires a 20 amp circuit breaker and 12/3 conductor wire from the panel to the VFD. You can also run single speed single phase motors up to 1.5 hp (check the motor ratings). Please note that single phase motors draw the most amperage during the initial startup.

115 volt supply with a 15 Amp breaker
The 115 volt setup is the most common in most garages. For the KBAC-24D, KB Electronics recommends using a 20 amp breaker. KB Electronics technical help desk has stated that the KBAC-24D can operate on a 115 volt 15 amp circuit. They recommend starting the drive at a slower RPM and then increasing to reduce the amperage draw on startup. You should research what circuits you have available in your garage and determine if anything else is running on that same circuit before proceeding. I would highly recommend using a 20 amp circuit.
Another other option would be to run a single speed 3600 RPM single phase motor on a 15 Amp circuit.  Most single phase 1 hp motors draw a maximum of 13 Amps.  A 1.5 hp single phase motors draw a maximum of 14.5 Amps.   Please note that single phase motors draw the most amperage during the initial startup.

Make sure you have the required power supply and circuit(s) with the applicable rated single or double pole breaker and conductor wire available to run the motor or VFD and motor. Please see the KBAC Table 4 Electrical rating chart for more information. Please check the motor information plate for the electrical ratings to ensure the motor you use is rated for the breaker and conductor wire.

Warning:
Working on electrical circuits or incorrectly connecting electrical equipment can be extremely hazardous. Please consult with qualified electrician and qualified personnel if you are unsure how to make safe electrical connections.  Electrical connections should meet or exceed National, Provincial, and local electrical codes. Always refer to the manufacture’s manuals and installation instructions. You may need permits if you are making changes or adding circuits to your electrical panel. Please check with your local authorities before starting any electrical connections.

How to choose the best sanding belt for your grinder?

There are 4 major categories of abrasive sanding belt material that are most common. These are, Aluminum Oxide, Zirconia (aka as Zirconia Alumina), Silicon Carbide and Ceramic.

Aluminum Oxide
Aluminum Oxide is a very common and relatively cheap belt available to purchase. Aluminum oxide works well on hard and soft woods, non-ferrous metals like aluminum and even on most grades of steel.

Zirconia
Zirconia is a man-made material and is very hard and works well in applications where high heat ocurrs from sanding hard materials especially in heavy removal applications. Zirconia is used for rough sanding or shaping of steel and stainless steel.

Silicon Carbide
Silicon Carbide is sharp and brittle. Most commonly found on wet & dry sanding sheets, Silicon Carbide is used for sanding glass, plastic, ceramic. It is also very popular in the very high grits for fine finishing on both metal.

Ceramic
Ceramic belts are a specially heat-treated aluminum oxide grain that is extremely hard. Although ceramic is more expensive to purchase, it last longer that Aluminum Oxide belts. Ceramic belts work really well to shape and in grinding hard metals such as Stainless Steel and Tool Steel. VSM Ceramic Plus belts are made in Canada and are great for knife makers.  Most Ceramic belts are in the lower grits 36 to 120 are the most commonly used.

Grit

  • Grits 16, 24, 36, 40, 50 & 60 are for material removal and rough shaping.
  • Grits 80, 100 & 120 are for smoothing surfaces and removing imperfections.
  • Grits 150, 180, 220, 240, 320, 400, 400, 600 and 800 are for final finishing.

Backing Material
There are 2 categories of backing material for sanding belts. They are paper backing and cloth backing.

Paper Backing
Paper backing is typically about 25% cheaper than cloth backed belts. The weight of the paper belt is identified by a letter. Belts are typically either “E-Weight” or “F-Weight”.

Cloth Backing
Cloth backing is the most durable and versatile backing material for sanding belts. The weight of the paper belt is identified by a letter.  The further into the alphabet you go, the heavier the backing material.

J-Weight is a light, flexible cloth backing that is suitable for applications where you are sanding over contours.
X-Weight is a medium weight backing that is good for general purpose use.
Y-Weight is a heavy duty backing with the most strength to withstand the pressure of heavy sanding and product removal.

Wet and Dry sand paper
We also sell sheets of Wet and Dry sand paper in starter packs. These VSM Wet Dry sheets are great for hand sanding your metal.

For more information, please see Nexus Grinders or VSM Abrasives Canada.

Variable Frequency Drive – KBAC AC Drive

KB Electronics KBAC AC Drive

Nexus Grinders is an authorized Canadian re-seller of KB Electronic Variable Frequency Drives. We ship only within Canada.

Variable Frequency Drives are commonly referred to as VFD’s. KB’s AC drives provide variable speed for 3ph AC Induction motors. If you want to use a VFD, you must use a 3-phase motor. You can’t use a single-phase motor on the industry standard VFD’s that most knife makers use for grinders. VFD’s convert single phase 115 or 230 volt inputs into 3-phase outputs to the motor. VFD’s control speed and also allow you to use forward and reverse settings with an optional switch.

You can’t use a motor that is rated higher than the VFD rating. You can use a higher rated VFD with a lower rated motor. So you can use a 2 horsepower VFD (KBAC-27d) with a 1 hp to 2 hp – 3 phase motors. You should not use a 1 horsepower VFD (KBAC-24d) with a 1.5 hp or 2 hp – 3 phase motor.

The three drives listed below are generally used for 1 to 3 HP – 3 phase motors.
* The KBAC -24D is recommended for 1.0 HP – 3 phase motors.
* The KBAC -27D is recommended for 1.0 HP, 1.5 HP & 2 HP – 3 phase motors, but most commonly used for 1.5 and 2 hp – 3 phase motors.
* The KBAC -29(1P) is recommended for 2.0 HP & 3 HP – 3 phase motors.

KBAC Hybrid Drive™ – NEMA 4X / IP65
The KBAC Series of Adjustable Frequency Drives consist of six inverter models rated for 1/8 to 5 horsepower motors. These drives are housed in heavy duty NEMA 4X / IP 65 die-cast aluminum washdown/watertight enclosures for indoor or outdoor use. Hybrid drives are a digital drive with an analog interface.  Warranty is 18 months from date of purchase.

Options available are:
On/Off AC Line Switch, Forward-Stop-Reverse Switch, Run-Stop-Jog Switch and Strain Relief Fittings.

Data Sheet
Manual 

If you are looking for other KB Electronic Drives such as the KBAC-29(1P) or have questions on KB Electronic drives, please contact Nexus Grinders. We also sell 3 phase motors for your VFD too.

How to make your belts last longer

The first question many people ask is, how long do belts last? The real question should be, what is the speed of your cutting and how fast can you remove material. 

We all want our belts to last as long as possible. The best practice is cleaning your grinder, wheels and platen on a regular basis. Cleaning will stop the grinding dust from building up on the back of your belts. The buildup of grinding dust on your wheels and platen will wear the back of your belt and the belt joint prematurely.

A sure telltale sign is looking at the back of your belt. If the writing is gone or your belt is black, your grinder dust is being transferred to the back of your belt. This can cause belt slip and also allow grinding dust to be deposited on your wheels and on your glass platen, which will impact your quality of flat grinding.

Enclosed are some quick simple steps to make your belts last longer.

  • use a dust extraction system with your grinder
  • if you don’t have an extraction system, ensure you clean your grinder, platen, and all of your aluminum wheels to remove the dust on a daily basis or more frequent if you are grinding a lot
  • clean your glass platen. The easiest way is to use Acetone to clean your glass. Second option is using a razor blade in a holder and lightly scrape the buildup on your glass platen at a 45-degree angle. Please use caution and scrap slowly and safely
  • store your belts in a dry environment
  • don’t leave your belts on your grinder when not in use

Always wear protective clothing and protective equipment when grinding.

Grinding Speeds Based On Material

Here are the industry standards that are recommended Surface Feet Per Minute (SFPM) based on work piece material.

Aluminum 4500 to 5000
Brass/Bronze 5000 to 6000
Grey Cast Iron 4000 to 5000
Nickel/Chrome 2500 – 3000
Mild/Carbon Steel 4000 to 5000
Titanium 2000 to 2500
Tool Steel 4000 to 5000

As a general rule, you will run 36 grit VSM Ceramic Plus belts at a higher RMP and 120 grit VSM Ceramic Plus belts at a slower speed. You can purchase VSM Ceramic Plus belts on our Nexus Grinders website.

Surface Feet Per Minute
Here is a simple grid to determine your SFPM based on a 4″, 5″ or 6″ drive wheel for a 2 x 72 belt grinder.

We sell 4″ and 5″ drive wheels for your grinding needs.

SOOW vs SJOOW Cable and Recommendations

SOOW and SJOOW are the best rated cords for power tools and equipment.  For Belt Grinders, we are going to discuss the differences between the two types of electrical cord and also the recommended wire sizes for your motors and Variable Frequency Drives. 

SOOW cord has a 600-volt rating.  SJOOW (J = junior service cord) is rated for 300 volts.  You can use either the 300 or 600 volt rated cord, but we recommend you use SJOOW cord as it’s cheaper and you don’t need 600 volt rating cord for most grinder motors and drives.

SOOW cord is incredibly durable. Its thermoset rubber jacket makes the cord weather resistant, and the jacket hardens under a direct application of heat, which allows the cord to be unaffected by aging, abrasion, water, sunlight and ozone. Oil-resistant insulation and jacketing lend to the cord’s durability as well.

SOOW wire can be submerged underwater and is flame retardant; therefore, it’s safe for all indoor and outdoor projects. The thermoset rubber won’t melt when it comes into contact with hot surfaces or oils. The cord is safe up to 221 degrees Fahrenheit, and it will even remain safe and flexible in temperatures as low as negative 40 degrees Fahrenheit.

The SJOOW version remains flexible and durable but is designed for indoor applications such as portable tools, equipment and motors.

Here are some recommendations.  Please do your own research or contact an electrician.

SJOOW 300 volt rating is our first choice for indoor applications.
SOOW 600 volt rating is our second choice, mostly due to costs.

You should also use strain reliefs for each connection in to your motor and VFD.
Strain relief 1/2” will work for 14/314/416/3 and 16/4 AWG.
Strain relief 3/4” for 10/310/4, 12/3 and 12/4 AWG.

14/3 or 14/4 AWG is rated at 15 Amps
12/3 or 12/4 AWG is rated at 20 Amps
10/3 or 10-4 AWG is rated at 30 Amps
* Check your motor Amperage to determine the correct wire gauge.

For 115 Volt or 230 volt Single Phase motors with cords up to 30’
1hp 1 phase 14/3 AWG
1.5hp 1 phase 12/3 AWG
2hp 1 phase 12/3 AWG
3hp 1 phase 10/3 AWG

For 230 volt Three Phase motors with KBAC 24d or 27d VFD’s:
 For 15 Amp supply 14/3 AWG to the VFD and 16/4 from the VFD to the motor.
For 20 Amp supply 12/3 AWG to the VFD and 16/4 from the VFD to the motor.
 For 30 Amp supply 10/3 AWG to the VFD and 16/4 from the VFD to the motor.

Warning:
These are our recommendations only.
Working on electrical circuits or incorrectly connecting electrical equipment can be extremely hazardous. Please consult with qualified electrician and qualified personnel if you are unsure how to make safe electrical connections.  Electrical connections should meet or exceed National, Provincial, and local electrical codes. Always refer to the manufacture’s manuals and installation instructions. You may need permits if you are making changes or adding circuits to your electrical panel. Please check with your local authorities before starting any electrical connections.

VSM Ceramic Plus 2×72 belts

Here at Nexus Grinders, we are proud to be a supplier of VSM Ceramic Plus 2 x 72 belts for our Canadian clients.

VSM Abrasives is one of the world’s leading manufacturers for high quality coated abrasives. With more than 150 years of experience, VSM understands abrasives like no one else.  

The VSM belts are manufactured at the VSM facility in Oakville, Ontario. Canadian made belts being sold by Nexus Grinders, a proud Canadian business.

VSM Abrasive Ceramic Plus belts have Improved self-sharpening characteristics and provide high stock removal rates and longer product life, when compared to traditional ceramic grain. They features cool cutting technology for reducing heat and increasing performance.

We are selling 36, 60, 80 and 120 Grit 2 x 72 Ceramic Plus belts.  We offer a great starter kit that has a variety of belt grits. We also offer single belts, packages of 5 and packages of 10.

Check out our website www.nexusgrinders.ca for more information and to purchase your very own VSM Ceramic Plus 2 x 72 belts.

We also sell VSM wet dry sand paper in sheets. We have put together variety pack of sheets to get you started. We can also sell you custom orders of wet dry sheets too.

Canadian Artisan

Canadian Artisan is a division of Noon’s Knives which is located in Rivers, Manitoba.
They supply high quality tools for leather carving and tooling. You can reach their knife making page at Canadian-Artisan

Contact Wheels for 2×72 Grinders

There are a lot of requests and questions regarding where to purchase contact wheels. As you know there are two types of contact wheels, smooth and serrated. They come in various diameters from 2″ to 14″ with 2″ widths. The most common sizes used are between 6 and 12 inches in diameter.

There are very few suppliers in North America with most being in the USA. Most of the US suppliers are re-selling items from Aliexpress. The other USA suppliers start around $300.00 cdn and prices go up from there.

Here at Nexus Grinders we have contracted to have 10″ contact wheels made specifically for us. These 10 x 2 inch serrated rubber contact wheels are great for hollow grinding or deburring. Our contact wheels are dynamically balanced an have a hardness of 70 euro.

Our Contact Wheels come with a 1/2″ diameter bolt with a CNC machined steel spacer specifically made for our Nexus Grinders.

Please see Nexus Grinders for more information.

Tracking Mechanism

When you start a new business, one of the challenges is finding the time to research, design, build and test new products. This week, I took some time to bench test our new 2 axis tracking mechanism. Although I usually leave the items in its raw steel state during testing, I added the pieces to the last order of powder coating. Well today, I started the bench testing and it performed exactly as it was designed. This new 2 axis tracking mechanism will make setup of all of the NG models easier for everyone. It will also allow for the fine adjustment when adding other attachments or for you blade smiths who like to run belts backwards.

Enclosed is short video demonstrating the fine tuning with the 2 axis tracking mechanism. The belt was purposely setup to be running into the grinder to demonstrate how the new mechanism works. The tracking wheel was set at 90 degrees from the frame. Adjusting the two socket cap screws allows the belt to be moved back to the centre of the tracking wheel and idler wheels. Once you have it dialled in, tighten the two screws and you’re done. This tracking mechanism allows you to adjust the tracking wheel in two different planes which makes setup so much easier.

The new 2 axis tracking mechanism is installed on all of the Nexus Grinders.

Bench Testing the Nexus 2 Axis Tracking Mechanism