As any veteran do-it-yourselfer knows, there are lot of mistakes made before you can call yourself an expert on anything. We all have experiences of home improvement projects that proved to be anything but an improvement. Usually these kind of mistakes just make us laugh and learn. But there are some home projects that cannot be done wrong because they are too dangerous to have a mistake with. Electrical repairs fall within this category. But if you follow these steps, you can make sure you keep yourself and your family safe when you do an electrical repair. Before you even take any of these steps, however, find out if your local community requires you to have a permit in order to do any electrical work. But these laws are different in each state, and even in each municipality, so check first.
The first thing you should do before you work on electricity is to turn the electric power off at the source. This must be done at the circuit breaker, since just turning off a wall switch will still leave you with hot wires.
Make sure the electric is off by using a voltage meter. After you have turned the electricity off at the circuit breaker, test the wire in the room you are working in and make sure nothing registers. Keep the power off until you have completed the job. You should not touch any of the electrical wires that bring electricity into the house. If you think there is something wrong With this service, make sure you contact your power company.
When you are working on electricity, never stand in water or even on a damp floor. Water conducts electricity, and it will go through you if it has to. If the floor is damp, put down a rubber mat.
Make sure you know what materials you are working with. In general, you have to be careful of metal, but rubber is safe. Since metal conducts electricity, do not touch metal at the same time you are touching a live wire, because you will become the conductant.
Since rubber is a nonconductive material, it will insulate you. So you should use tools with rubber or plastic handles, and wear rubber soled shoes or sneakers. While we are on the subject of what to wear, you should also wear safety goggles and gloves.
Now that you have completed the repair, flip the circuit breaker back on to turn on the power. Use you voltage meter once again to see if there is power, and there is the right amount of voltage. Smaller items such as lights, a receptacle or a small appliance will need 120 volts. Big appliances (air conditioners, ovens, etc.) will require 240 volts. There are some appliances that need such small voltage, such as doorbells or telephones that they will have a transformer to convert the power to a smaller voltage.
If you want to make sure you know what you are doing before you start an electrical repair job, you may consider taking advantage of the clinics or workshops that many do-it-yourself centers offer. You will learn a lot and feel more confident when you tackle the next job. If you don't feel that you know what you are doing, don't take a chance: call an expert electrician to do this kind of work. There are plenty of other jobs you can do, such as painting, hanging shelves, or trimming branches. Just ask your wife. She probably has a "honey do" list as well as cnc routers and used cnc electronics all ready and waiting for you.
Wednesday, December 19, 2007
Inexpensive PCs as CNC Machine Controllers
There are two main groups that can take advantage of today�s low cost PCs as an effective and inexpensive CNC controller.
� Retrofits to existing CNC machines with outdated or proprietary controls in need of service.
� Shop built and home built CNC machines.
Inexpensive PCs can cost as little as $150.00 and yet provide a dependable and effective CNC machine controller. Some sources to consider for obtaining such a system are outpost.com and dell.com. Oupost.com is an outlet for Fry�s electronics. They have one PC on sale ranging from $150.00 to $199.00. Several have successfully used this PC in conjunction with MACH2 CNC controller software.
Tradeoffs: Price vs. Quality. With the lowest cost PCs there a tradeoff in performance, quality, and reliability. The manufacturers of these machines use low cost hardware in their manufacture and they make compromises in the design of the systems to keep their costs down. Inexpensive hardware translates directly to a higher failure rate and more difficult to obtain manufacturer support. This can be a deciding factor by itself if you rely on this machine for production.
Design compromises which are common in low cost PC have an impact on performance. The primary concerns are: insufficient memory, the use of shared memory, and on-board graphics devices. The primary hardware requirements for a PC based CNC controller are sufficient memory, and sufficient processor speed. You can see that the compromises present in these systems are in direct opposition to the requirements for CNC controller.
At the bottom end of the Inexpensive PC market there are off the self solutions that will function well as a PC based CNC controller. As with all things, you tend to get what you pay for, so the buyer is advised to be aware of the requirements and limitations that are in play.
Part II in this series of articles will examine an alternative to buying an off the shelf solution and explore building a PC to meet your specifications.
� Retrofits to existing CNC machines with outdated or proprietary controls in need of service.
� Shop built and home built CNC machines.
Inexpensive PCs can cost as little as $150.00 and yet provide a dependable and effective CNC machine controller. Some sources to consider for obtaining such a system are outpost.com and dell.com. Oupost.com is an outlet for Fry�s electronics. They have one PC on sale ranging from $150.00 to $199.00. Several have successfully used this PC in conjunction with MACH2 CNC controller software.
Tradeoffs: Price vs. Quality. With the lowest cost PCs there a tradeoff in performance, quality, and reliability. The manufacturers of these machines use low cost hardware in their manufacture and they make compromises in the design of the systems to keep their costs down. Inexpensive hardware translates directly to a higher failure rate and more difficult to obtain manufacturer support. This can be a deciding factor by itself if you rely on this machine for production.
Design compromises which are common in low cost PC have an impact on performance. The primary concerns are: insufficient memory, the use of shared memory, and on-board graphics devices. The primary hardware requirements for a PC based CNC controller are sufficient memory, and sufficient processor speed. You can see that the compromises present in these systems are in direct opposition to the requirements for CNC controller.
At the bottom end of the Inexpensive PC market there are off the self solutions that will function well as a PC based CNC controller. As with all things, you tend to get what you pay for, so the buyer is advised to be aware of the requirements and limitations that are in play.
Part II in this series of articles will examine an alternative to buying an off the shelf solution and explore building a PC to meet your specifications.
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