125A 4P Molded Case Circuit Breaker in stock

About us  
Zhejiang Safesave Electrical Technology Co., Ltd was invested and build by Shanghai Shuen Electrical Technology Co., Ltd. Safesave focuses on high- voltage and low-voltage electrical equipment, electrical complete units and industrial automation devices. Our products have been applied to some national key projects such as Shanghai World Expo, Beijing Olympic stadiums, South–to-North Water Division Project, Pudong international airport. Meanwhile , the factory was titled as a high-technology enterprise, science and technology enterprise, software enterprise, advanced enterprise in quality management, etc.
Our company cooperates with the partners from outstanding university research units such as Mechanical and Electrical Engineering and Automation Academy of Shanghai University, Information and Technology Academy of Fudan University. After the reorganization, the factory will do further research and manufacturing in high-end industrial automation equipment on the basis of previous achievement in the field of soft starter and variable frequency drive.
Brief Company’s Developing History  
In 2000——The first thyristor motor soft starter was developed with independent research, making our company one of the earliest manufacturers of the soft starter in China;
In 2003——The factory was moved to Shanghai;
In 2005——The second generation of intelligent soft starter and the variable frequency drive were certified as Shanghai new and high technology transformation achievements;
In 2006——Identified as Shanghai high-tech enterprise;
In 2007——A new generation of vector variable frequency drive was put into large-scale production;
Moved into Caohejing Economic and Technological Development Zone of Shanghai City
In 2008——Products were applied to the swimming center and shooting center of Beijing Olympic Games in batches.
In 2010——Production was applied in Shanghai World Expo;
Build up cooperation relationship with Fudan university optoelectronic department and Organize the photovoltaic inverter research laboratory.
In 2014——Regrouped and moved to Songjiang national economic and technological development zone of Shanghai City;
Build up strategic cooperation relationship with Chint Group and Delix Group, and became the sole official supplier of the core inverting components of EPS power products for the two groups.
In 2015——SY9000 devises were successfully developed and put into trial-production;
Meanwhile, the professional research team of servo motor and servo controller were organized.
In 2016——A new setting-free, quick-start, compacted, foolproof soft starters named SJR3—N has been developed successfully and put into trial-production.
Safesave’s Culture  
To create a greener world with our safe and energy-saving technology.
To be a happy corporation benefiting human society.
Gratitude: Thankfulness for God’s grace, team cooperation and clients’ trust.
Credibility: Fruitful promise and resultful action.
Dedication: Persistence in seeking for professional perfection.
Teamwork: A promotive spirit of sharing, cherishing , cooperation and positive mutual influence .
Responsibility:Courage of taking responsibility for whatever result with no excuse.
Passion: Full energy and fighting will.
Learning: Consistent learning of professional skills to gain efficient working ability.
Innovation: A force to change the backward and lead the market.
Sharing: Growth in what we share.
The R&D Team  
1.Structure of the R &D Center
The R&D center of Zhejiang Saikong Electrical Technology consists of three sections, namely, Electronic Design( systematic analysis and electronic circuits), Structural Design(heat dissipation design, configuration design), and Measurement and Verification(simulation and analysis, test and verification)
The R &D center has an experienced research and development team, working closely with Scientific Research Departments of the Institute of Mechanical and Electrical Engineering and Automation of Shanghai University, the Science and Technology Institute, and the Information Technology Department of Fudan University.
With years of efforts, Saikong has developed more than 100 models of 10 series of products by our outstanding talents and technology.
2.Business range & Achievements in recently years.
The R &D center’s design mainly covers two areas: power electronics; energy-saving and emission-reduction. Main products includes mid-low voltage soft starter, mid-low voltage frequency converter, AC servo controller,servo motor, etc.
During the years from 2013 to 2016, the R &D center has successfully developed SST type of intelligent soft starter with built-in bypass, SJR3 series of intelligent soft starter, 5000 type of online intelligent soft starter with built-in bypass, SN-100G series, SY9000 series of open loop vector inverter, G5 series of closed-loop vector inverter, SN-200G series of closed-loop vector inverter, waterproof type of inverter, EPS uninterruptible power supply, permanent magnet synchronous motor and etc., totally more than 100 models of 10 series of products. Meanwhile, we have completed the corresponding CAPP system of computer aided process planning , sound product database and process documents, etc.of each series of products.
Meanwhile, the center has applied for over twenty technical patents, including 4 invention patents, 14 patents of new utility models, 6 structure patents, 3 software copyright patents. Up until the end of 2016, 3 of our new invention patents have been publicly announced and are to be approved.
In recent years , led by a trend of miniaturization, intelligence, networking, and profession in product development, a batch of new high-tech products have been developed in succession, such as SST type of intelligent soft starter , 5000 type of online intelligent soft starter, SN-200G series of closed-loop vector inverter, which has greatly raised the popularity and reputation of our company in this field. Along with increasing application of our products in the fields of manufacturing, elevatoring, hoisting, machine tooling, printing&packaging, textile&chemical fibre, constructuring, metallurgy, mining, metro, etc, Saikong is making a great contribution to the cause of automatic control , energy-saving and emission-reduction for our country with our advanced and reliable products.
3.Investments on our R &D center.
To enhance the competence in the business field and and creativity for the sustainable development of our company, Saikong places high priority to the scientific research capability, keeping aggrandizing the investment and strength of research for new products. R & D investment takes over 30% of the total budget, and the R &D crew takes up 24.6% of the whole workforce.
4.Brief introduction of key staff at the R &D center
The R &D team is lead by Professor Zhao, the chief engineer, who has been in the field of power electronic for many years and who has been devoted into researching and developing a new generation’s frequency converter, soft starter, servo controller, servomotor. A complete set of solutions including proposal selection, structure designing, hardware designing, software designing, testing, quality guarantee, is delivered from our main researching staff of over 8 years’ industrial experience on average.
The center now has 25 staff, the majority were graduated from key universities majored in telecom, electric machinery. Among them, there are two professor of advanced engineers, 8 senior engineers, 14 engineers.Meanwhile, we also hire industrial-renowned experts in inverter/designing/technics as our consultants.
Leading Core EngineersPositionBrief Introduction
Engineer ZhaoTechnical director/Chief engineerBorn in 1972, aged 45, Eng. Zhao is working with Electric Machinery Institute of Shanghai University as supervisor for students of bachelors, masters and doctors.Having been long engaged in designing and developing hardware and software relevant to electronic inverting technology in power field, integrated with capabilities of project management, systemic analyse and designing , having been worked as technological chief supervisor or chief engineer in succession in several big companies, and having developed more than 100 new models of 10 series of products of inverters, soft starters, servo controllers and solar inverters, Eng. Zhao is now enjoys very good reputation in the industry.
Engineer LiProject engineer/System utility engineerBorn in 1961, aged 56, with Bachelor’s Degree majored in Industry Automation. Eng. Li is a pioneer in designing low-voltage soft starter in China. As the earliest designer of low-voltage soft starter in China, he led the designing of China’s first generation of soft starter and achieved success.
Engineer WangHardware engineerBorn in 1978, aged 38, with Master’s Degree, majored in Electronic Information Engineering Technology. Eng. Wang has been engaged in researching and development of frequency converter for many years, and has insightful views in SMPS and inverter drive.
Engineer YiSoftware engineerBorn in 1979, aged 37, with Master’s Degree.Having long been engaged in software compiling, Eng. Yi is very familiar with all types of software coding tools, and has good working capability and industrial experience.
Engineer ZhuHardware engineerBorn in 1981, aged 35, with Bachelor’s Degree, graduated from Hefei Industrial University, majored in Engineering Automation.Expertised in systemic adjustments, techinical identification, Eng. Zhu has insightful views in electronic circuit, data collecting, failure analysis.
5.Decent experiment environment.
To guarantee the reliability of the products that have been developed, the center established two well-equipped high-standard labs that cover 500 square meters.One serves to test regular features and performance.The other is to conduct performance tests under extreme circumstances.
We purchased complete equipments despite of high cost to enable the experimental process from simulating the spot environment, technic data collecting, to data processing and technique analysis digitized, visualized, and trackable. Each sample product is no longer a sample but a device having experienced practical application, and each data is no longer lab data but high-simulated spot data. In this way we fundamentally guarantee data accuracy at the spot environment and full-time reliability of the products.
List of main experimental equipment at R &D center
NO.Equipment /InstrumentFunction
1Standard equipment and standard devices:
Voltage source (constant voltage, adjustable), current source (constant current, adjustable), signal source (adjustable), standard resistance, standard capacitance, standard inductance, etc..To guarantee the accuracy of all the equipments and testing data.
2Testing equipments for regular data:
Voltage meter, current meter, multimeter, clamp meter, megger, small signal RMS current meter, DC current generator, oscilloscope, LCR BridgeRegular data of general voltage, current, resistance, capacitance, inductance, signal waveform tests
3A variety of test equipments for special parameters:
Power analyzer, spectrum analyzer, power analyzer, thermal zone imager, temperature management instrument, tachometer, flow meter, pressure gauge, balance machine etc..For testing of special parameter data and the data collected under specific circumstances.Such as test s for temperature, wind speed, flow, pressure, turning speed, strength of magnetic field, balance, coil rolling, wire diameter and power factor analysis, frequency spectrum analysis.
4A variety of special test equipments:
NC high pressure machine, surge generator, pulse group generator, etc.To test data parameters for special projects, such as high voltage protection, creepage distance, electrical clearance, EMC interference, lightning resistance, etc.
5A variety of equipments simulating field work environment:
NC high temperature chamber (0-300°C), NC low temperature chamber (0- minus 150°C), automatic ON/OFF experiment system, dust test box, acid/salt fog test box, shaft to drag load system (0-1000A, AC), vibration testing system(1-200KG), drop test equipment etc..For testing of the performance and data of spare parts or complete equipment which operate under extreme circumstances.To ensure the products work in all regions in high reliability.
6Various reliability test equipments:
Automatic ON/OFF aging room, high and low temperature cycle impact equipment, high temperature aging chamber with load, anti interference test room, etc.To test the reliability, stability, consistency, device life and other parameters of the components or the whole machine.
6. R&D Orientation in future
Along with society development, technical progress, and the revolutionary changes in the fields of domestic industrial automation control, energy-saving and emission-reduction, our R&D center keeps refreshing percepts , optimizing the products. Oriented by the goal to achieve miniaturization, multi-function, digitization, network, specialization and modularization, we believe, in the very near future the new products launched by our R&D center will dominate the industry.
7.Strict management system and practical working style
“No best, only better”
This is the working attitude and pursuit of our R&D center.
“Engaged in the basic work, down to the earth to try the best in everything.”
This is the basic requirement set by our own R &D members.
At the R &D center, design work is processed in modular, plural and step procedure, and management weighs responsibility, data and performance.The center highly values coordination among departments and among managers, and emphasizes the whole team’s working efficiency.
For each project, the center has clear target and thoughts. To complete the project, the center adopts quantitative management. Specific division of labor is distributed to each person and node time is set on daily basis so that the whole team becomes a strong, cohesive and centripetal force, working like a sophisticated engine to achieve a shared output target through all parts’ orderly, tensive and enthusiastic work.
Q1: Are you a manufacturer or a trading company?
A1: We are a manufacturer.
Q2: Can I get some samples?
A2: Yes, sample order is available for quality check and market test. After we receive the sample charge, the samples will be delivered in 7-15 days.
Q3: Can you do the design for us?
A3: Yes. We have a professional designing team. Just tell us your ideas and we will help to carry out your ideas. Send us high resolution images, your Logo and text and tell us how you would like to arrange them, We will send you finished files for confirmation.
Q4: What about the delivery time?
A4: It depends on the quantity and the season you place the order. It usually takes about 7-15 days for production.
Q5: What is your terms of delivery?
A5: We accept EXW, FOB, CFR, CIF, etc. You can choose the one which is the most convenient or cost effective for you.
Q6: What’s your warranty terms?
A6: We offer 1 year warranty time.125A 4P Molded Case Circuit Breaker in stock

Update value in same view using CASE expression

I am creating a view where i have daily data of different items and each item has a state. I created a column that shows what the column was yesterday using

LAG(state) OVER(PARTITION BY item_id ORDER BY currentdate) AS yesterday_state 

Now I want to count how long the state has been the same value and im doing so with this:

COUNT (CASE WHEN state = yesterday_state THEN state ELSE NULL END) OVER(PARTITION BY item_id ORDER BY currentdate AS state_age 

This is working properly but I need to find a way to set the value back to 0 when state != yesterday_state

This all is happening inside of SELECT statement as I’m creating a view. How could I go around doing this so that the state_age sets to 0 when state is not the same value as yesterday_state

Basing average case hardness from worst case hardness

I am trying to understand the current knowledge about questions of the form: “If a language $ L$ is difficult on the worse case, then there exists a distribution $ D$ such that it is difficult to solve $ L$ on instances drawn from $ D$ “.

  1. Random self reducibility captures this concept: it asks if it is possible to reduce the problem of solving arbitrary instance $ x \in L$ to solving a set of random instances. In AGGM it is shown that unless the polynomial time hierarchy collapses, there is no $ L \in NPC$ which is randomized self reducible. It means that it is unlikely that we can prove that some $ L$ is hard on average assuming only that $ L$ is hard in worst case.
  2. For circuits, seems that the situation is a bit different: Impaglizaao’s hardcore lemma (informally) states that if $ L$ cannot be solved on a fraction of $ 1-\delta$ of the inputs of size $ n$ by a circuit of size $ S$ , then there exists a distribution such that no circuit of roughly the same size can solve more than $ 0.5 + \epsilon$ of the inputs. Thus, if we had a worse case hard language $ L$ , we could build a “difficult distribution”.

First, I don’t understand how these results settle: unless the polynomial hierarchy collapses, $ SAT \notin P/poly$ , which means that every polynomial size circuit $ C_n$ can solve at most fraction of $ 1-\delta$ of the inputs, so by Impaglizaao’s hardcore lemma it is possible to construct a distribution over $ SAT$ which is hard for all polynomial circuits – assuming only worst case assumptions.

Second, are there known results about hardcore sets for uniform computation (i.e. Turing machines)?

What is the use case of request signing in this mobile app?

The API of a mobile app I was testing is receiving the AWS AccessKeyId and SecretKey used for request signing from the AWS Cognito server unencrypted (apart from the regular TLS encryption). Making it possible to re-sign all requests to their AWS Lambda API, e.g. using Burp’s “AWS Signer” extension.

With this, a Man-In-The-Middle could sign all altered requests, so I wonder what the actual use case of request signing is, in this instance?

Shouldn’t the AccessKeyID and SecretKey be kept secret?

The owner of the app is telling me that this is not an issue because they are following the AWS guidelines.

Is that correct? Or are they doing something wrong?

Why would they sign the requests in the first place in their mobile app? What is the use case of signing the requests, when the ‘secrets’ for creating a signature are distributed via the same connection in clear (except TLS)?

Is this conform with best practices, when using AWS Lambda for serverless mobile app APIs? Is request signing even useful in this instance? Most apps I have tested didn’t use request signing.

Approach for algorithm to find closest 3-D object in a list of many similar objects to a given test case

Lets say I have a list of many (10s of thousands – millions) objects, and each of these objects has a given number of 3-D vertices (my current implementation uses 8 vertices each, but this number can be reduced if it causes a very significant increase in performance). These vertices are currently stored as floats from 0-255, but this range can also be changed if need be, assuming it will not reduce accuracy too drastically. Also, I can store these objects in any data structure that would be beneficial for this algorithm.

I am given another such object, also with the same number (8) 3-D vertices, but of which in general it must be assumed that none of the vertices are common with any vertices included in the list of stored previous objects.

With all of this in mind, I need an algorithm that will return an object from that list that is optimally close to the test case object (close being defined in the normal, euclidean distance, sense). By optimally close, I mean that it does not have to be the global optimum if this will greatly increase performance, although if there is a quick algorithm that will always return the global optimum i would love to hear it.

Euclidean algorithm – runtime in specific case

I’m going to solving many times this specific equations:

$ $ 2^{x+y} \cdot c – a^{y} \cdot z = 1$ $

in which $ $ a$ $ can be equal to: $ $ -7,-5,-3,-1,1,3,5,7$ $ . And $ $ x+y$ $ will be equal to $ $ 128$ $ It has to be done with euclidean algorithm, but how many step it requiers in average in this specific case?

I know that euclidean algoritm requires at least $ $ log(b) \cdot 5$ $ steps, where b is the smaller number, but in this case we don’t know which number will be smaller $ $ 2^{x+y}$ $ or $ $ a^{y}$ $ that’s why I have a problem with this case.

How can merging two sorted arrays of N items require at least 2N – 1 comparisons in every case?

The HW question, on page 362 of Data Structures and Algorithms in C++: Fourth Editionby Mark Allen Weiss, reads as follows:

Prove that merging two sorted arrays of N items requires at least 2 * N – 1 comparisons. You must show that if two elements in the merged lists are consecutive and from different lists, then they must be compared

If we are trying to find the lower bound then wouldn’t the number of comparisons be N, not 2 * N – 1? If the largest element is some array Ais smaller than the smallest element in some array B then at most you would only have to do N comparisons since after all of A‘s elements are placed in the merged array then the remaining elements in B‘s can simply be appended in to the merged array.

The lower bound has to be something that is true for every possible N and every possible combination of elements in both arrays, right? 2 * N – 1 seems more like it would be the upper bound since there is no way there can be more comparisons than that.

Note: I am not asking for an answer to the HW question itself as I know that is deprecated. I am confused about the implied assertion the question is making about the lower bound